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1. The TESS–Keck Survey. XIX. A Warm Transiting Sub-Saturn-mass Planet and a Nontransiting Saturn-mass Planet Orbiting a Solar Analog

Author: Michelle L. Hill, Stephen R. Kane, Paul A. Dalba, Mason MacDougall, Tara Fetherolf, Zhexing Li, Daria Pidhorodetska, Natalie M. Batalha, Ian J. M. Crossfield, Courtney Dressing, Benjamin Fulton, Andrew W. Howard, Daniel Huber, Howard Isaacson, Erik A. Petigura, Paul Robertson, Lauren M. Weiss, Aida Behmard, Corey Beard, Ashley Chontos, Fei Dai, Steven Giacalone, Lea A. Hirsch, Rae Holcomb, Jack Lubin, Andrew W. Mayo, Teo Močnik, Joseph M. Akana Murphy, Alex S. Polanski, Lee J. Rosenthal, Ryan A. Rubenzahl, Nicholas Scarsdale, Emma V. Turtelboom, Judah Van Zandt, Allyson Bieryla, David R. Ciardi, Jason D. Eastman, Ben Falk, Katharine M. Hesse, David W. Latham, John Livingston, Rachel A. Matson, Elisabeth Matthews, George R. Ricker, Alexander Rudat, Joshua E. Schlieder, S. Seager, and Joshua N. Winn
Subjects: Exoplanets, Exoplanet astronomy, Exoplanet detection methods, Radial velocity, Transit photometry, Photometry, Astronomy, QB1-991
Abstract: The Transiting Exoplanet Survey Satellite (TESS) continues to increase dramatically the number of known transiting exoplanets, and is optimal for monitoring bright stars amenable to radial velocity (RV) and atmospheric follow-up observations. TOI-1386 is a solar-type (G5V) star that was detected via TESS photometry to exhibit transit signatures in three sectors with a period of 25.84 days. We conducted follow-up RV observations using Keck/High Resolution Echelle Spectrometer (HIRES) as part of the TESS–Keck Survey, collecting 64 RV measurements of TOI-1386 with the HIRES spectrograph over 2.5 yr. Our combined fit of the TOI-1386 photometry and RV data confirm the planetary nature of the detected TESS signal, and provide a mass and radius for planet b of 0.148 ± 0.019 M _J and 0.540 ± 0.017 R _J , respectively, marking TOI-1386 b as a warm sub-Saturn planet. Our RV data further reveal an additional outer companion, TOI-1386 c, with an estimated orbital period of 227.6 days and a minimum mass of 0.309 ± 0.038 M _J . The dynamical modeling of the system shows that the measured system architecture is long-term stable, although there may be substantial eccentricity oscillations of the inner planet due to the dynamical influence of the outer planet.
Published: 2024
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2. High-resolution Imaging of a TESS Control Sample: Verifying a Deficit of Close-in Stellar Companions to Exoplanet Host Stars

Author: Colin Littlefield, Steve B. Howell, David R. Ciardi, Kathryn V. Lester, Mark E. Everett, Elise Furlan, Rachel A. Matson, Sergio B. Fajardo-Acosta, and Crystal L. Gnilka
Subjects: Speckle interferometry, Exoplanet astronomy, Astronomy, QB1-991
Abstract: The large number of exoplanets discovered with the Transiting Exoplanet Survey Satellite (TESS) means that any observational biases from TESS could influence the derived stellar multiplicity statistics of exoplanet host stars. To investigate this problem, we obtained speckle interferometry of 207 control stars whose properties in the TESS Input Catalog (TIC) closely match those of an exoplanetary host star in the TESS Object of Interest (TOI) catalog, with the objective of measuring the fraction of these stars that have companions within ∼1.″2. Our main result is the identification of a bias in the creation of the control sample that prevents the selection of binaries with 0.″1 ≲ ρ ≲ 1.″2 and Δmag ≲3. This bias is the result of large astrometric residuals that cause binaries with these parameters to fail the quality checks used to create the TIC, which in turn causes them to have incomplete stellar parameters (and uncertainties) in the TIC. Any stellar multiplicity study that relies exclusively upon TIC stellar parameters to identify its targets will struggle to select unresolved binaries in this parameter space. Left uncorrected, this selection bias disproportionately excludes high-mass-ratio binaries, causing the mass-ratio distribution of the companions to deviate significantly from the uniform distribution expected of FGK-type field binaries. After accounting for this bias, the companion rate of the FGK control stars is consistent with the canonical 46% ± 2% rate from Raghavan et al., and the mass-ratio distribution agrees with that of binary TOI host stars. There is marginal evidence that the control-star companions have smaller projected orbital separations than TOI host stars from previous studies.
Published: 2024
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3. Editorial: The Effect of Stellar Multiplicity on Exoplanetary Systems

Author: Steve B. Howell, Rachel A. Matson, and Francesco Marzari
Subjects: binary stars, exoplanets, multiple stars, circumbinary planets, habitability, occurrence rates, Astronomy, QB1-991, Geophysics. Cosmic physics, QC801-809
Published: 2022
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4. TESS Spots a Super-puff: The Remarkably Low Density of TOI-1420b

Author: Stephanie Yoshida, Shreyas Vissapragada, David W. Latham, Allyson Bieryla, Daniel P. Thorngren, Jason D. Eastman, Mercedes López-Morales, Khalid Barkaoui, Charles Beichman, Perry Berlind, Lars A. Buchave, Michael L. Calkins, David R. Ciardi, Karen A. Collins, Rosario Cosentino, Ian J. M. Crossfield, Fei Dai, Victoria DiTomasso, Nicholas Dowling, Gilbert A. Esquerdo, Raquel Forés-Toribio, Adriano Ghedina, Maria V. Goliguzova, Eli Golub, Erica J. Gonzales, Ferran Grau Horta, Jesus Higuera, Nora Hoch, Keith Horne, Steve B. Howell, Jon M. Jenkins, Jessica Klusmeyer, Didier Laloum, Jack J. Lissauer, Sarah E. Logsdon, Luca Malavolta, Rachel A. Matson, Elisabeth C. Matthews, Kim K. McLeod, Jennifer V. Medina, Jose A. Muñoz, Hugh P. Osborn, Boris Safonov, Joshua Schlieder, Michael Schmidt, Heidi Schweiker, Sara Seager, Alessandro Sozzetti, Gregor Srdoc, Guđmundur Stefánsson, Ivan A. Strakhov, Stephanie Striegel, Joel Villaseñor, and Joshua N. Winn
Subjects: Exoplanets, Transits, Exoplanet structure, Astronomy, QB1-991
Abstract: We present the discovery of TOI-1420b, an exceptionally low-density ( ρ = 0.08 ± 0.02 g cm ^−3 ) transiting planet in a P = 6.96 days orbit around a late G-dwarf star. Using transit observations from TESS, LCOGT, Observatoire Privé du Mont, Whitin, Wendelstein, OAUV, Ca l’Ou, and KeplerCam, along with radial velocity observations from HARPS-N and NEID, we find that the planet has a radius of R _p = 11.9 ± 0.3 R _⊕ and a mass of M _p = 25.1 ± 3.8 M _⊕ . TOI-1420b is the largest known planet with a mass less than 50 M _⊕ , indicating that it contains a sizeable envelope of hydrogen and helium. We determine TOI-1420b’s envelope mass fraction to be ${f}_{\mathrm{env}}={82}_{-6}^{+7} \% $ , suggesting that runaway gas accretion occurred when its core was at most four to five times the mass of the Earth. TOI-1420b is similar to the planet WASP-107b in mass, radius, density, and orbital period, so a comparison of these two systems may help reveal the origins of close-in low-density planets. With an atmospheric scale height of 1950 km, a transmission spectroscopy metric of 580, and a predicted Rossiter–McLaughlin amplitude of about 17 m s ^−1 , TOI-1420b is an excellent target for future atmospheric and dynamical characterization.
Published: 2023
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5. Visual Orbits and Alignments of Planet-hosting Binary Systems

Author: Kathryn V. Lester, Steve B. Howell, Rachel A. Matson, Elise Furlan, Crystal L. Gnilka, Colin Littlefield, David R. Ciardi, Mark E. Everett, Sergio B. Fajardo-Acosta, and Catherine A. Clark
Subjects: Binary stars, Exoplanet systems, Planet hosting stars, Astrometric binary stars, Astronomy, QB1-991
Abstract: Roughly half of Solar-type planet hosts have stellar companions, so understanding how these binary companions affect the formation and evolution of planets is an important component to understanding planetary systems overall. Measuring the dynamical properties of planet host binaries enables a valuable test of planet formation in multistar systems and requires knowledge of the binary orbital parameters. Using high-resolution imaging, we have measured the relative astrometry and visual orbits of 13 binary systems where one of the stars is known to host a transiting exoplanet. Our results indicate that the mutual inclination between the orbits of the binary hosts and the transiting planets are well aligned. Our results for close binary systems ( a < 100 au) complement past work for wide planet host binaries from Gaia.
Published: 2023
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6. Twin High-Resolution, High-Speed Imagers for the Gemini Telescopes: Instrument Description and Science Verification Results

Author: Nicholas J. Scott, Steve B. Howell, Crystal L. Gnilka, Andrew W. Stephens, Ricardo Salinas, Rachel A. Matson, Elise Furlan, Elliott P. Horch, Mark E. Everett, David R. Ciardi, Dave Mills, and Emmett A. Quigley
Subjects: astronomical instrumentation, speckle interfcromctry, multiple stars, ground-based astronomy, optical astronomy, Astronomy, QB1-991, Geophysics. Cosmic physics, QC801-809
Abstract: Two new imaging instruments, ‘Alopeke and Zorro, were designed, built, and commissioned at the Gemini-North and Gemini-South telescopes in 2018 and 2019, respectively. Here we describe them and present the results from over a year of operation. The two identical instruments are based on the legacy of the DSSI (Differential Speckle Survey Instrument) instrument, successfully used for years at the WIYN and the Gemini telescopes in Hawaii and Chile. ‘Alopeke and Zorro are dual-channel imagers having both speckle (6.7″) and “wide-field” (∼1 arcminute) field-of-view options. They were built to primarily perform speckle interferometry providing diffraction-limited imagery at optical wavebands, yielding pixel scale uncertainties of ±0.21 mas, position angle uncertainties of ±0.7◦, and photometric uncertainties of Δm ± 0.02–0.04 magnitudes (for the blue and red channels, respectively) when run through the standard data reduction pipeline. One of their main scientific roles is the validation and characterization of exoplanets and their host stars as discovered by transit surveys such as the NASA Kepler, K2, and TESS missions. The limiting magnitude for speckle observations at Gemini can be quite faint (r ∼18 in good observing conditions) but typically the observed targets are brighter. The instruments can also function as conventional CCD imagers providing a 1 arc-minute field of view and allowing simultaneous two-color, high-speed time-series operation. These resident visitor instruments are remotely operable and are available for use by the community via the peer-reviewed proposal process.
Published: 2021
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7. Corrigendum: The NASA High-Resolution Speckle Interferometric Imaging Program: Validation and Characterization of Exoplanets and Their Stellar Hosts

Author: Steve B. Howell, Nicholas J. Scott, Rachel A. Matson, Mark E. Everett, Elise Furlan, Crystal L. Gnilka, David R. Ciardi, and Kathryn V. Lester
Subjects: exoplanets, exoplanetary systems, binary host stars, speckle interferometry, high-resolution imaging, Astronomy, QB1-991, Geophysics. Cosmic physics, QC801-809
Published: 2021
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8. The NASA High-Resolution Speckle Interferometric Imaging Program: Validation and Characterization of Exoplanets and Their Stellar Hosts

Author: Steve B. Howell, Nicholas J. Scott, Rachel A. Matson, Mark E. Everett, Elise Furlan, Crystal L. Gnilka, David R. Ciardi, and Kathryn V. Lester
Subjects: exoplanets, high-resolution imaging, speckle interferometry, binary stars, exoplanet demographics, Astronomy, QB1-991, Geophysics. Cosmic physics, QC801-809
Abstract: Starting in 2008, NASA has provided the exoplanet community an observational program aimed at obtaining the highest resolution imaging available as part of its mission to validate and characterize exoplanets, as well as their stellar environments, in search of life in the Universe. Our current program uses speckle interferometry in the optical (320–1,000 nm) with new instruments on the 3.5-m WIYN and both 8-m Gemini telescopes. Starting with Kepler and K2 follow-up, we now support TESS and other space- and ground-based exoplanet related discovery and characterization projects. The importance of high-resolution imaging for exoplanet research comes via identification of nearby stellar companions that can dilute the transit signal and confound derived exoplanet and stellar parameters. Our observations therefore provide crucial information allowing accurate planet and stellar properties to be determined. Our community program obtains high-resolution imagery, reduces the data, and provides all final data products, without any exclusive use period, to the community via the Exoplanet Follow-Up Observation Program (ExoFOP) website maintained by the NASA Exoplanet Science Institute. This paper describes the need for high-resolution imaging and gives details of the speckle imaging program, highlighting some of the major scientific discoveries made along the way.
Published: 2021
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9. TOI 560: Two Transiting Planets Orbiting a K Dwarf Validated with iSHELL, PFS, and HIRES RVs

Author: Mohammed El Mufti, Peter P. Plavchan, Howard Isaacson, Bryson L. Cale, Dax L. Feliz, Michael A. Reefe, Coel Hellier, Keivan Stassun, Jason Eastman, Alex Polanski, Ian J. M. Crossfield, Eric Gaidos, Veselin Kostov, Justin M. Wittrock, Joel Villaseñor, Joshua E. Schlieder, Luke G. Bouma, Kevin I. Collins, Farzaneh Zohrabi, Rena A. Lee, Ahmad Sohani, John Berberian, David Vermilion, Patrick Newman, Claire Geneser, Angelle Tanner, Natalie M. Batalha, Courtney Dressing, Benjamin Fulton, Andrew W. Howard, Daniel Huber, Stephen R. Kane, Erik A. Petigura, Paul Robertson, Arpita Roy, Lauren M. Weiss, Aida Behmard, Corey Beard, Ashley Chontos, Fei Dai, Paul A. Dalba, Tara Fetherolf, Steven Giacalone, Michelle L. Hill, Lea A. Hirsch, Rae Holcomb, Jack Lubin, Andrew Mayo, Teo Močnik, Joseph M. Akana Murphy, Lee J. Rosenthal, Ryan A. Rubenzahl, Nicholas Scarsdale, Christopher Stockdale, Karen Collins, Ryan Cloutier, Howard Relles, Thiam-Guan Tan, Nicholas J Scott, Zach Hartman, Elisabeth Matthews, David R. Ciardi, Erica Gonzales, Rachel A. Matson, Charles Beichman, Allyson Bieryla, E. Furlan, Crystal L. Gnilka, Steve B. Howell, Carl Ziegler, César Briceño, Nicholas Law, Andrew W. Mann, Markus Rabus, Marshall C. Johnson, Jessie Christiansen, Laura Kreidberg, David Anthony Berardo, Drake Deming, Varoujan Gorjian, Farisa Y. Morales, Björn Benneke, Diana Dragomir, Robert A. Wittenmyer, Sarah Ballard, Brendan P. Bowler, Jonathan Horner, John Kielkopf, Huigen Liu, Avi Shporer, C. G. Tinney, Hui Zhang, Duncan J. Wright, Brett C. Addison, Matthew W. Mengel, and Jack Okumura
Subjects: Radial velocity, Astronomy, QB1-991
Abstract: We validate the presence of a two-planet system orbiting the 0.15–1.4 Gyr K4 dwarf TOI 560 (HD 73583). The system consists of an inner moderately eccentric transiting mini-Neptune (TOI 560 b, $P={6.3980661}_{-0.0000097}^{+0.0000095}$ days, $e={0.294}_{-0.062}^{+0.13}$ , $M={0.94}_{-0.23}^{+0.31}{M}_{\mathrm{Nep}}$ ) initially discovered in the Sector 8 Transiting Exoplanet Survey Satellite (TESS) mission observations, and a transiting mini-Neptune (TOI 560 c, $P={18.8805}_{-0.0011}^{+0.0024}$ days, $M={1.32}_{-0.32}^{+0.29}{M}_{\mathrm{Nep}}$ ) discovered in the Sector 34 observations, in a rare near-1:3 orbital resonance. We utilize photometric data from TESS Spitzer, and ground-based follow-up observations to confirm the ephemerides and period of the transiting planets, vet false-positive scenarios, and detect the photoeccentric effect for TOI 560 b. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with the iSHELL spectrograph at the NASA Infrared Telescope Facility and the HIRES Spectrograph at Keck Observatory to validate the planetary nature of these signals, which we combine with published Planet Finder Spectrograph RVs from the Magellan Observatory. We detect the masses of both planets at >3 σ significance. We apply a Gaussian process (GP) model to the TESS light curves to place priors on a chromatic RV GP model to constrain the stellar activity of the TOI 560 host star, and confirm a strong wavelength dependence for the stellar activity demonstrating the ability of near-IR RVs to mitigate stellar activity for young K dwarfs. TOI 560 is a nearby moderately young multiplanet system with two planets suitable for atmospheric characterization with the James Webb Space Telescope and other upcoming missions. In particular, it will undergo six transit pairs separated by
Published: 2022
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10. TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet

Author: Ares Osborn, David J Armstrong, Bryson Cale, Rafael Brahm, Robert A Wittenmyer, Fei Dai, Ian J M Crossfield, Edward M Bryant, Vardan Adibekyan, Ryan Cloutier, Karen A Collins, E Delgado Mena, Malcolm Fridlund, Coel Hellier, Steve B Howell, George W King, Jorge Lillo-Box, Jon Otegi, S Sousa, Keivan G Stassun, Elisabeth C Matthews, Carl Ziegler, George Ricker, Roland Vanderspek, David W Latham, S Seager, Joshua N Winn, Jon M Jenkins, Jack S Acton, Brett C Addison, David R Anderson, Sarah Ballard, David Barrado, Susana C C Barros, Natalie Batalha, Daniel Bayliss, Thomas Barclay, Björn Benneke, John Berberian, Francois Bouchy, Brendan P Bowler, César Briceño, Christopher J Burke, Matthew R Burleigh, Sarah L Casewell, David Ciardi, Kevin I Collins, Benjamin F Cooke, Olivier D S Demangeon, Rodrigo F Díaz, C Dorn, Diana Dragomir, Courtney Dressing, Xavier Dumusque, Néstor Espinoza, P Figueira, Benjamin Fulton, E Furlan, E Gaidos, C Geneser, Samuel Gill, Michael R Goad, Erica J Gonzales, Varoujan Gorjian, Maximilian N Günther, Ravit Helled, Beth A Henderson, Thomas Henning, Aleisha Hogan, Saeed Hojjatpanah, Jonathan Horner, Andrew W Howard, Sergio Hoyer, Dan Huber, Howard Isaacson, James S Jenkins, Eric L N Jensen, Andrés Jordán, Stephen R Kane, Richard C Kidwell, John Kielkopf, Nicholas Law, Monika Lendl, M Lund, Rachel A Matson, Andrew W Mann, James McCormac, Matthew W Mengel, Farisa Y Morales, Louise D Nielsen, Jack Okumura, Hugh P Osborn, Erik A Petigura, Peter Plavchan, Don Pollacco, Elisa V Quintana, Liam Raynard, Paul Robertson, Mark E Rose, Arpita Roy, Michael Reefe, Alexandre Santerne, Nuno C Santos, Paula Sarkis, J Schlieder, Richard P Schwarz, Nicholas J Scott, Avi Shporer, A M S Smith, C Stibbard, Chris Stockdale, Paul A Strøm, Joseph D Twicken, Thiam-Guan Tan, A Tanner, J Teske, Rosanna H Tilbrook, C G Tinney, Stephane Udry, Jesus Noel Villaseñor, Jose I Vines, Sharon X Wang, Lauren M Weiss, Richard G West, Peter J Wheatley, Duncan J Wright, Hui Zhang, and F Zohrabi
Published: 2021
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11. TOI-1231 b: A Temperate, Neptune-sized Planet Transiting the Nearby M3 Dwarf NLTT 24399

Author: Jennifer A. Burt, Diana Dragomir, Paul Mollière, Allison Ann Youngblood, Antonio García Muñoz, John McCann, Laura Kreidberg, Chelsea X. Huang, Karen A. Collins, Jason D. Eastman, Lyu Abe, Jose M. Almenara, Ian J. M. Crossfield, Carl Ziegler, Joseph E. Rodriguez, Eric E. Mamajek, Keivan G. Stassun, Samuel P. Halverson, Steven Villanueva Jr, R. Paul Butler, Sharon Xuesong Wang, Richard P Schwarz, George R. Ricker, Roland Vanderspek, David W. Latham, S. Seager, Joshua N. Winn, Jon M. Jenkins, Abdelkrim Agabi, Xavier Bonfils, David Ciardi, Marion Cointepas, Jeffrey D. Crane, Nicolas Crouzet, Georgina Dransfield, Fabo Feng, Elise Furlan, Tristan Guillot, Arvind F. Gupta, Steve B. Howell, Eric L. N. Jensen, Nicholas Law, Andrew W. Mann, Wenceslas Marie-Sainte, Rachel A. Matson, Elisabeth C. Matthews, Djamel Mékarnia, Joshua Pepper, Nic Scott, Stephen A. Shectman, Joshua E. Schlieder, François-Xavier Schmider, Daniel J. Stevens, Johanna K. Teske, Amaury H. M. J. Triaud, David Charbonneau, Zachory K. Berta-Thompson, Christopher J. Burke, Tansu Daylan, Thomas Barclay, Bill Wohler, and C. E. Brasseur
Subjects: Astronomy, Astrophysics
Abstract: We report the discovery of a transiting, temperate, Neptune-sized exoplanet orbiting the nearby (d = 27.5 pc), M3V star TOI-1231 (NLTT 24399, L 248-27, 2MASS J10265947-5228099). The planet was detected using photometric data from the Transiting Exoplanet Survey Satellite and followed up with observations from the Las Cumbres Observatory and the Antarctica Search for Transiting ExoPlanets program. Combining the photometric data sets, we find that the newly discovered planet has a radius of 3.65(+0.16,-0.15)Rꚛ and an orbital period of 24.246 days. Radial velocity measurements obtained with the Planet Finder Spectrograph on the Magellan Clay telescope confirm the existence of the planet and lead to a mass measurement of 15.5 ± 3.3 Mꚛ. With an equilibrium temperature of just 330 K, TOI-1231 b is one of the coolest small planets accessible for atmospheric studies thus far, and its host star's bright near-infrared brightness (J = 8.88, Ks = 8.07) makes it an exciting target for the Hubble Space Telescope and the James Webb Space Telescope. Future atmospheric observations would enable the first comparative planetology efforts in the 250–350 K temperature regime via comparisons with K2-18 b. Furthermore, TOI-1231's high systemic radial velocity (70.5 km/s) may allow for the detection of low-velocity hydrogen atoms escaping the planet by Doppler, shifting the H i Lyα stellar emission away from the geocoronal and interstellar medium absorption features.
Published: 2021
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12. TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images

Author: Joseph E. Rodriguez, Samuel N. Quinn, George Zhou, Andrew Vanderburg, Louise D. Nielsen, Robert A. Wittenmyer, Rafael Brahm, Phillip A. Reed, Chelsea X. Huang6, Sydney Vach, David R. Ciardi, Ryan J. Oelkers, Keivan G. Stassun, Coel Hellier, B. Scott Gaudi, Jason D. Eastman, Karen A. Collins, Allyson Bieryla, Sam Christian, David W. Latham, Ilaria Carleo, Duncan J. Wright, Elisabeth Matthews, Erica J. Gonzales, Carl Ziegler, Courtney D. Dressing, Steve B. Howell, Thiam-Guan Tan, Justin Wittrock, Peter Plavchan, Kim K. McLeod, David Baker, Gavin Wang, Don J. Radford, Richard P. Schwarz, Massimiliano Esposito, George R. Ricker, Roland K. Vanderspek, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Brett Addison, D. R. Anderson, Thomas Barclay, Thomas G. Beatty, Perry Berlind, Francois Bouchy, Michael Bowen, Brendan P. Bowler, C. E. Brasseur, César Briceño, Douglas A. Caldwell, Michael L. Calkins, Scott Cartwright, Priyanka Chaturvedi, Guillaume Chaverot, Sudhish Chimaladinne, Jessie L. Christiansen, Kevin I. Collins, Ian J. M. Crossfield, Kevin Eastridge, Néstor Espinoza, Gilbert A. Esquerdo, Dax L. Feliz, Tyler Fenske, William Fong, Tianjun Gan, Steven Giacalone, Holden Gill, Lindsey Gordon, A. Granados, Nolan Grieves, Eike W. Guenther, Natalia Guerrero, Thomas Henning, Christopher E. Henze, Katharine Hesse, Melissa J. Hobson, Jonathan Horner, David J. James, Eric L. N. Jensen, Mary Jimenez, Andres Jordan, Stephen R. Kane, John Kielkopf, Kingsley Kim, Rudolf B. Kuhn, Natasha Latouf2, Nicholas M. Law, Alan M. Levine, Michael B. Lund, Andrew W. Mann, Shude Mao, Rachel A. Matson, Matthew W. Mengel, Jessica Mink, Patrick Newman2, Tanner O Dwyer, Jack Okumura, Enric Palle, Joshua Pepper, Elisa V. Quintana, Paula Sarkis, Arjun B. Savel, Joshua E. Schlieder, Chloe Schnaible, Avi Shporer, Ramotholo Sefako, Julia V. Seidel, Robert J. Siverd, Brett Skinner, Manu Stalport, Daniel J. Stevens, Caitlin Stibbards, C. G. Tinney, R. G. West, Daniel A. Yahalomi, and Hui Zhang
Subjects: Astronomy
Abstract: We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b(TIC 281408474; HD288842), TOI-640 b(TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC409794137), and TOI-1601 b (TIC 139375960)—based on data from NASA’s Transiting Exoplanet Survey Satellite(TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (RP=1.01–1.77RJ) and have masses that range from 0.85 to 6.33MJ. The host stars of these systems have F and G spectral types (5595Teff 6460 K)and are all relatively bright (9.51.7RJ, possibly a result of its host star’s evolution) and resides on an orbit with a period longer than 5 days. TOI-628 b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of-+6.310.300.28MJ and a statistically significant, nonzero orbital eccentricity of e=-+0.0740.0220.021. This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478 b (P=10.18 days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA’s TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals.
Published: 2021
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13. TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star

Author: Brett C. Addison, Duncan J. Wright, Belinda A. Nicholson, Bryson Cale, Teo Mocnik, Daniel Huber, Peter Plavchan, Robert A. Wittenmyer, Andrew Vanderburg, William J. Chaplin, Ashley Chontos, Jake T. Clark, Jason D. Eastman, Carl Ziegler, Rafael Brahm, Bradley D. Carter, Mathieu Clerte, Nestor Espinoza, Jonathan Horner, John Bentley, Andres Jordan, Stephen R. Kane, John F. Kielkopf, Emilie Laychock, Matthew W. Mengel, Jack Okumura, Keivan G. Stassun, Timothy R. Bedding, Brendan P. Bowler, Andrius Burnelis, Sergi Blanco-Cuaresma, Michaela Collins, Ian Crossfield, Allen B. Davis, Dag Evensberget, Alexis Heitzmann, Steve B. Howell, Nicholas Law, Andrew W. Mann, Stephen C. Marsden, Rachel A. Matson, James H. O’Connor, Avi Shporer, Catherine Stevens, C. G. Tinney, Christopher Tylor, Songhu Wang, Hui Zhang, Thomas Henning, Diana Kossakowski, George Ricker, Paula Sarkis, Martin Schlecker, Pascal Torres, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Ismael Mireles, Pam Rowden, Joshua Pepper, Tansu Daylan, Joshua E. Schlieder, Karen A. Collins, Kevin I. Collins, Thiam-Guan Tan, Warrick H. Ball, Sarbani Basu, Derek L. Buzasi, Tiago L. Campante, Enrico Corsaro, L. Gonz´alez-Cuesta, Guy R. Davies, Leandro de Almeida, Jose-Dias do Nascimento Jr, Rafael A. Garcpıa, Zhao Guo, Rasmus Handberg, Saskia Hekker, Daniel R. Hey, Thomas Kallinger, Steven D. Kawaler, Cenk Kayhan, James S. Kuszlewicz, Mikkel N. Lund, Alexander Lyttle, Savita Mathur, Andrea Miglio, Benoit Mosser, Martin B. Nielsen, Aldo M. Serenelli, Victor Silva Aguirre, and Nathalie Themeßl
Subjects: Astrophysics
Abstract: We report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based on data from NASA’s Transiting Exoplanet Survey Satellite (TESS). The transit signal was detected by TESS and confirmed to be of planetary origin based on radial velocity observations. An analysis of the TESS photometry, the MINERVA-Australis, FEROS, and HARPS radial velocities, and the asteroseismic data of the stellar oscillations reveals that TOI-257b has a mass of M(P) = 0.138 ± 0.023 M(J) (43.9 ± 7.3 Mꚛ), a radius of R(P) = 0.639 ± 0.013 R(J) (7.16 ± 0.15 Rꚛ⁠), bulk density of 0.65 (+0.12,−0.11) (cgs), and period 18.38818 (+0.00085,−0.00084) days⁠. TOI-257b orbits a bright (V = 7.612 mag) somewhat evolved late F-type star with M⁎ = 1.390 ± 0.046 M(sun)⁠, R⁎ = 1.888 ± 0.033 R(sun)⁠, T(eff) = 6075 ± 90 K⁠, and 𝜈sin 𝑖 = 11.3 ± 0.5 km/s. Additionally, we find hints for a second non-transiting sub-Saturn mass planet on a ∼71 day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars (∼100) that have been characterized with asteroseismology. Warm sub-Saturns are rare in the known sample of exoplanets, and thus the discovery of TOI-257b is important in the context of future work studying the formation and migration history of similar planetary systems.
Published: 2020
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14. The First Habitable-zone Earth-sized Planet from TESS. I. Validation of the TOI-700 System

Author: Emily A. Gilbert, Thomas Barclay, Joshua E. Schlieder, Elisa V. Quintana, Benjamin J. Hord, Veselin B. Kostov, Eric D. Lopez, Jason F. Rowe, Kelsey Hoffman, Lucianne M. Walkowicz, Michele L. Silverstein, Joseph E. Rodriguez, Andrew Vanderburg, Gabrielle Suissa, Vladimir S. Airapetian, Matthew S. Clement, Sean N. Raymond, Andrew W. Mann, Ethan Kruse, Jack J. Lissauer, Knicole D. Colón, Ravi kumar Kopparapu, Laura Kreidberg, Sebastian Zieba, Karen A. Collins, Samuel N. Quinn, Steve B. Howell, Carl Ziegler, Eliot Halley Vrijmoet, Fred C. Adams, Giada N. Arney, Patricia T. Boyd, Jonathan Brande, Christopher J. Burke, Luca Cacciapuoti, Quadry Chance, Jessie L. Christiansen, Giovanni Covone, Tansu Daylan, Danielle Dineen, Courtney D. Dressing, Zahra Essack, Thomas J. Fauchez, Brianna Galgano, Alex R. Howe, Lisa Kaltenegger, Stephen R. Kane, Christopher Lam, Eve J. Lee, Nikole K. Lewis, Sarah E. Logsdon, Avi M. Mandell, Teresa Monsue, Fergal Mullally, Susan E. Mullally, Rishi R. Paudel, Daria Pidhorodetska, Peter Plavchan, Naylynn Tañón Reyes, Stephen A. Rinehart, Bárbara Rojas-Ayala, Jeffrey C. Smith, Keivan G. Stassun, Peter Tenenbaum, Laura D. Vega, Geronimo L. Villanueva, Eric T. Wolf, Allison Youngblood, George R. Ricker, Roland K. Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Gáspár Å. Bakos, César Briceño, David R. Ciardi, Ryan Cloutier, Dennis M. Conti, Andrew Couperus, Mario Di Sora, Nora L. Eisner, Mark E. Everett, Tianjun Gan, Joel D. Hartman, Todd Henry, Giovanni Isopi, Wei-Chun Jao, Eric L. N. Jensen, Nicholas Law, Franco Mallia, Rachel A. Matson, Benjamin J. Shappee, Mackennae Le Wood, and Jennifer G. Winters
Subjects: Astronomy, Astrophysics
Abstract: We present the discovery and validation of a three-planet system orbiting the nearby (31.1 pc) M2 dwarf star TOI-700 (TIC 150428135). TOI-700 lies in the TESS continuous viewing zone in the Southern Ecliptic Hemisphere; observations spanning 11 sectors reveal three planets with radii ranging from 1 R⊕ to 2.6 R⊕ and orbital periods ranging from 9.98 to 37.43 days. Ground-based follow-up combined with diagnostic vetting and validation tests enables us to rule out common astrophysical false-positive scenarios and validate the system of planets. The outermost planet, TOI-700 d, has a radius of 1.19 ± 0.11 R⊕ and resides within a conservative estimate of the host star's habitable zone, where it receives a flux from its star that is approximately 86% of Earth's insolation. In contrast to some other low-mass stars that host Earth-sized planets in their habitable zones, TOI-700 exhibits low levels of stellar activity, presenting a valuable opportunity to study potentially rocky planets over a wide range of conditions affecting atmospheric escape. While atmospheric characterization of TOI-700 d with the James Webb Space Telescope (JWST) will be challenging, the larger sub-Neptune, TOI-700 c (R = 2.63 R⊕), will be an excellent target for JWST and future space-based observatories. TESS is scheduled to once again observe the Southern Hemisphere, and it will monitor TOI-700 for an additional 11 sectors in its extended mission. These observations should allow further constraints on the known planet parameters and searches for additional planets and transit timing variations in the system.
Published: 2020
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15. KELT-25 b and KELT-26 b: A Hot Jupiter and a Substellar Companion Transiting Young A Stars Observed by TESS

Author: Romy Rodríguez Martínez, B. Scott Gaudi, Joseph E. Rodriguez, George Zhou, Jonathan Labadie-Bartz, Samuel N. Quinn, Kaloyan Penev, Thiam-Guan Tan, David W. Latham, Leonardo A. Paredes, John F. Kielkopf, Brett C. Addison, Duncan J. Wright, Johanna Teske, Steve B Howell, David R Ciardi, Carl Ziegler, Keivan G. Stassun, Marshall C. Johnson, Jason D. Eastman, Robert J. Siverd, Thomas G. Beatty, Luke Bouma, Timothy Bedding, Joshua Pepper, Joshua N. Winn, Michael B. Lund, Steven Villanueva Jr, Daniel J. Stevens, Eric L. N. Jensen, Coleman Kilby, Jeffrey D. Crane, Andrei Tokovinin, Mark E. Everett, Chris G. Tinney, Michael Martin Fausnaugh, David H Cohen, Daniel Bayliss, Allyson Bieryla, Phillip A. Cargile, Karen A. Collins, Dennis M. Conti, Knicole Colon, Ivan A. Curtis, D. L. Depoy, Phil Evans, Dax L. Feliz, Joao Gregorio, Jason Rothenberg, David J. James, Michael D. Joner, Rudolf B. Kuhn, Mark Manner, Somayeh Khakpash, Jennifer L. Marshall, Kim K. McLeod, Matthew T. Penny, Phillip A. Reed, Howard M. Relles, Denise C. Stephens, Chris Stockdale, Mark Trueblood, Pat Trueblood, Xinyu Yao, Roberto Zambelli, Roland Vanderspek, Sara Seager, Jon M Jenkins, Todd J. Henry, Hodari-Sadiki James, Wei-Chun Jao, Sharon Xuesong Wang, Aaron Paul Butler, Ian Thompson, Stephen Shectman, Robert A. Wittenmyer, Brendan P. Bowler, Jonathan Horner, Stephen R. Kane, Matthew W. Mengel, Timothy D. Morton, Jack Okumura, Peter Plavchan, Hui Zhang, Nicholas Joseph Scott, Rachel A. Matson, Andrew W. Mann, Diana Dragomir, Max Günther, Eric B Ting, Ana Glidden, and Elisa Victoria Quintana
Subjects: Astronomy
Abstract: We present the discoveries of KELT-25 b (TIC 65412605, TOI-626.01) and KELT-26 b (TIC 160708862, TOI-1337.01), two transiting companions orbiting relatively bright, early A stars. The transit signals were initially detected by the KELT survey and subsequently confirmed by Transiting Exoplanet Survey Satellite (TESS) photometry. KELT-25 b is on a 4.40 day orbit around the V=9.66 star CD-24 5016(=-+T8280eff180440K,Må=-+2.180.110.12Me), while KELT-26 b is on a 3.34 day orbit around the V=9.95 star HD 134004 (Teff=-+8640240500K,Må=-+1.930.160.14Me), which is likely an Am star. We have confirmed the substellar nature of both companions through detailed characterization of each system using ground-based and TESS photometry, radial velocity measurements, Doppler tomography, and high-resolution imaging. For KELT-25, we determine a companion radius of RP=-+1.640.0430.039RJ and a 3σupper limit on the companion’s mass of64MJ. For KELT-26 b, we infer a planetary mass and radius of MP=-+1.410.510.43MJ and RP=-+1.940.0580.060RJ. From Doppler tomographic observations, we find KELT-26 b to reside in a highly misaligned orbit. This conclusion is weakly corroborated by a subtle asymmetry in the transit light curve from the TESS data. KELT-25 b appears to be in a well-aligned, prograde orbit, and the system is likely a member of the cluster Theia 449.
Published: 2020
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16. TOI-1235 b: A Keystone Super-Earth for Testing Radius Valley Emergence Models around Early M Dwarfs

Author: Ryan Cloutier, Joseph E. Rodriguez, Jonathan Irwin, David Charbonneau, Keivan G. Stassun, Annelies Mortier, David W. Latham, Howard Isaacson, Andrew W. Howard, Stéphane Udry, Thomas G. Wilson, Christopher A. Watson, Matteo Pinamonti, Florian Lienhard, Paolo Giacobbe, Pere Guerra, Karen A. Collins, Allyson Beiryla, Gilbert A. Esquerdo, Elisabeth Matthews, Rachel A. Matson, Steve B. Howell, Elise Furlan, Ian J. M. Crossfield, Jennifer G. Winters, Chantanelle Nava, Kristo Ment, Eric D. Lopez, George Ricker, Roland Vanderspek, Sara Seager, Jon M. Jenkins, Eric B. Ting, PeterTenenbaum, Alessandro Sozzetti, Lizhou Sha, Damien Ségransan, Joshua E. Schlieder, Dimitar Sasselov, Arpita Roy, Paul Robertson, Ken Rice, Ennio Poretti, Giampaolo Piotto, David Phillips, Joshua Pepper, Francesco Pepe, Emilio Molinari, Teo Mocnik, Giuseppina Micela, Michel Mayor, Aldo F. Martinez Fiorenzano, Franco Mallia, Jack Lubin, Christophe Lovis, Mercedes López-Morales, Molly R. Kosiarek, John F. Kielkopf, Stephen R. Kane, Eric L. N. Jensen, Giovanni Isopi, Daniel Huber, Michelle L. Hill, Avet Harutyunyan, Erica Gonzales, Steven Giacalone, Adriano Ghedina, Andrea Ercolino, Xavier Dumusque, Courtney D. Dressing, Mario Damasso, Paul A. Dalba, Rosario Cosentino, Dennis M. Conti, Knicole D. Colón, Kevin I. Collins, Andrew Collier Cameron, David Ciardi, Jessie Christiansen, Ashley Chontos, Massimo Cecconi, Douglas A. Caldwell, Christopher Burke, Lars Buchhave, Charles Beichman, Aida Behmard, Corey Beard, and Joseph M. Akana Murphy
Subjects: Astronomy, Astrophysics
Abstract: Small planets on close-in orbits tend to exhibit envelope mass fractions of either effectively zero or up to a few percent depending on their size and orbital period. Models of thermally driven atmospheric mass loss and of terrestrial planet formation in a gas-poor environment make distinct predictions regarding the location of this rocky/nonrocky transition in period–radius space. Here we present the confirmation of TOI-1235 b (P = 3.44 days, r(p)=1.738 (+0.087, -0.076) Rꚛ), a planet whose size and period are intermediate between the competing model predictions, thus making the system an important test case for emergence models of the rocky/nonrocky transition around early M dwarfs (R(s) = 0.630 ± 0.015 Rꙩ, M(s) = 0.640 ± 0.016 Mꙩ}$). We confirm the TESS planet discovery using reconnaissance spectroscopy, ground-based photometry, high-resolution imaging, and a set of 38 precise radial velocities (RVs) from HARPS-N and HIRES. We measure a planet mass of 6.91 (+0.75, -0.85) Mꚛ, which implies an iron core mass fraction of 20 (+15,-12)% in the absence of a gaseous envelope. The bulk composition of TOI-1235 b is therefore consistent with being Earth-like, and we constrain an H/He envelope mass fraction to be <0.5% at 90% confidence. Our results are consistent with model predictions from thermally driven atmospheric mass loss but not with gas-poor formation, suggesting that the former class of processes remains efficient at sculpting close-in planets around early M dwarfs. Our RV analysis also reveals a strong periodicity close to the first harmonic of the photometrically determined stellar rotation period that we treat as stellar activity, despite other lines of evidence favoring a planetary origin P= 21.8(+0.9, _0.8) days, m(p)sin i= 13.0 (+3.8,-5.3) Mꚛ) that cannot be firmly ruled out by our data.
Published: 2020
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17. TESS Spots a Hot Jupiter with an Inner Transiting Neptune

Author: Chelsea X Huang, Samuel N Quinn, Andrew Vanderburg, Juliette Becker, Joseph E Rodriguez, Francisco J Pozuelos, Davide Gandolfi, George Zhou, Andrew W Mann, Karen A Collins, Ian Crossfield, Khalid Barkaoui, Kevin I Collins, Malcolm Fridlund, Michaël Gillon, Erica J Gonzales, Maximilian N Günther, Todd J Henry, Steve B Howell, Hodari-Sadiki James, Wei-Chun Jao, Emmanuël Jehin, Eric L N Jensen, Stephen R Kane, Jack J Lissauer, Elisabeth Matthews, Rachel A Matson, Leonardo A Paredes, Joshua E Schlieder, Keivan G Stassun, Avi Shporer, Lizhou Sha, Thiam-Guan Tan, Iskra Georgieva, Savita Mathur, Enric Pallé, Carina M Persson, Vincent Van Eylen, George R Ricker, Roland K Vanderspek, David W Latham, Joshua N Winn, S Seager, Jon M Jenkins, Christopher J Burke, Robert F Goeke, Stephen Rinehart, Mark E Rose, Eric B Ting, Guillermo Torres, and Ian Wong
Subjects: Astronomy
Abstract: Hot Jupiters are rarely accompanied by other planets within a factor of a few in orbital distance. Previously, only two such systems have been found. Here, we report the discovery of a third system using data from the Transiting Exoplanet Survey Satellite (TESS). The host star, TOI-1130, is an eleventh magnitude K-dwarf in Gaia G-band. It has two transiting planets: a Neptune-sized planet (3.65±0.10 Rꚛ) with a 4.1 days period, and a hot Jupiter (-1.50(+0.22,-0.27) R(J)) with an 8.4 days period. Precise radial-velocity observations show that the mass of the hot Jupiter is -0.974(+0.044, 0.043) M(J). For the inner Neptune, the data provide only an upper limit on the mass of 0.17M(J)(3σ). Nevertheless, we are confident that the inner planet is real, based on follow-up ground-based photometry and adaptive-optics imaging that rule out other plausible sources of the TESS transit signal. The unusual planetary architecture of and the brightness of the host star make TOI-1130 a good test case for planet formation theories, and an attractive target for future spectroscopic observations.
Published: 2020
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18. Validation of 13 Hot and Potentially Terrestrial TESS Planets

Author: Steven Giacalone, Courtney D. Dressing, Christina Hedges, Veselin B. Kostov, Karen A. Collins, Eric L. N. Jensen, Daniel A. Yahalomi, Allyson Bieryla, David R. Ciardi, Steve B. Howell, Jorge Lillo-Box, Khalid Barkaoui, Jennifer G. Winters, Elisabeth Matthews, John H. Livingston, Samuel N. Quinn, Boris S. Safonov, Charles Cadieux, E. Furlan, Ian J. M. Crossfield, Avi M. Mandell, Emily A. Gilbert, Ethan Kruse, Elisa V. Quintana, George R. Ricker, S. Seager, Joshua N. Winn, Jon M. Jenkins, Britt Duffy Adkins, David Baker, Thomas Barclay, David Barrado, Natalie M. Batalha, Alexander A. Belinski, Zouhair Benkhaldoun, Lars A. Buchhave, Luca Cacciapuoti, David Charbonneau, Ashley Chontos, Jessie L. Christiansen, Ryan Cloutier, Kevin I. Collins, Dennis M. Conti, Neil Cutting, Scott Dixon, René Doyon, Mohammed El Mufti, Emma Esparza-Borges, Zahra Essack, Akihiko Fukui, Tianjun Gan, Kaz Gary, Mourad Ghachoui, Michaël Gillon, Eric Girardin, Ana Glidden, Erica J. Gonzales, Pere Guerra, Elliott P. Horch, Krzysztof G. Hełminiak, Andrew W. Howard, Daniel Huber, Jonathan M. Irwin, Giovanni Isopi, Emmanuël Jehin, Taiki Kagetani, Stephen R. Kane, Kiyoe Kawauchi, John F. Kielkopf, Pablo Lewin, Lindy Luker, Michael B. Lund, Franco Mallia, Shude Mao, Bob Massey, Rachel A. Matson, Ismael Mireles, Mayuko Mori, Felipe Murgas, Norio Narita, Tanner O’Dwyer, Erik A. Petigura, Alex S. Polanski, Francisco J. Pozuelos, Enric Palle, Hannu Parviainen, Peter P. Plavchan, Howard M. Relles, Paul Robertson, Mark E. Rose, Pamela Rowden, Arpita Roy, Arjun B. Savel, Joshua E. Schlieder, Chloe Schnaible, Richard P. Schwarz, Ramatholo Sefako, Aleksandra Selezneva, Brett Skinner, Chris Stockdale, Ivan A. Strakhov, Thiam-Guan Tan, Guillermo Torres, René Tronsgaard, Joseph D. Twicken, David Vermilion, Ian A. Waite, Bradley Walter, Gavin Wang, Carl Ziegler, and Yujie Zou
Published: 2022
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19. A systematic validation of hot Neptunes in TESS data

Author: Christian Magliano, Giovanni Covone, Richa Dobal, Luca Cacciapuoti, Luca Tonietti, Steven Giacalone, Jose I Vines, Laura Inno, James S Jenkins, Jack J Lissauer, Allyson Bieryla, Fabrizio Oliva, Isabella Pagano, Veselin Kostov, Carl Ziegler, David R Ciardi, Erica J Gonzales, Courtney D Dressing, Lars A Buchhave, Steve B Howell, Rachel A Matson, Elisabeth Matthews, Alessandra Rotundi, Douglas Alves, Stefano Fiscale, Riccardo M Ienco, Pablo Peña, Francesco Gallo, and Maria T Muscari Tomajoli
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), techniques: photometric, planets and satellites: detection, Space and Planetary Science, astro-ph.EP, FOS: Physical sciences, planets and satellites: general, Astronomy and Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We statistically validated a sample of hot Neptune candidates applying a two-step vetting technique using DAVE and TRICERATOPS. We performed a systematic validation of 250 transit-like events in the Transiting Exoplanet Survey Satellite (TESS) archive in the parameter region defined by $P\leq 4$ d and $3R_\oplus\leq R\leq 5R_\oplus$. Through our analysis, we identified 18 hot Neptune-sized candidates, with a false positive probability $, 24 pages, 20 figures. Accepted for publication on MNRAS
Published: 2023

20. The L 98-59 System: Three Transiting, Terrestrial-size Planets Orbiting a Nearby M Dwarf

Author: Veselin B Kostov, Joshua E Schlieder, Thomas Barclay, Elisa V Quintana, Knicole D Colon, Jonathan Brande, Karen A. Collins, Adina D. Feinstein, Samuel Hadden, Stephen R. Kane, Laura Kreidberg, Ethan Kruse, Christopher Lam, Elisabeth Matthews, Benjamin T. Montet, Francisco J. Pozuelos, Keivan G. Stassun, Jennifer G. Winters, George R Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua Winn, Jon M Jenkins, Dennis Afanasev, James D Armstrong, Giada N Arney, Patricia Boyd, Geert Barentsen, Khalid Barkaoui, Natalie E. Batalha, Charles A Beichman, Daniel Bayliss, Christopher Burke, Artem Burdanov, Luca Cacciapuoti, Andrew Carson, David Charbonneau, Jessie Christiansen, David R Ciardi, Mark Clampin, Kevin I Collins, Dennis M. Conti, Jeffrey Langer Coughlin, Giovanni Covone, Ian Crossfield, Laetitia Delrez, Shawn David Domagal-goldman, Courtney Dressing, Elsa Ducrot, Zahra Essack, Mark E. Everett, Thomas Fauchez, Daniel Foreman-Mackey, Tianjun Gan, Emily Anne Gilbert, Michaël Gillon, Erica Gonzales, Aaron Hamann, Christina Louise Hedges, Hannah Hocutt, Kelsey Hoffman, Elliott P. Horch, Keith Horne, Steve B Howell, Shane Joseph Hynes, Michael Ireland, Jonathan M. Irwin, Giovanni Isopi, Eric L. N. Jensen, Emmanuël Jehin, Lisa Kaltenegger, John F. Kielkopf, Ravi Kumar Kopparapu, Nikole Lewis, Eric David Lopez, Jack J Lissauer, Andrew W. Mann, Franco Mallia, Avram Mandell, Rachel A. Matson, Tsevi Mazeh, Teresa A Monsue, Sarah E. Moran, Vickie Moran, Caroline V. Morley, Brett Morris, Philip Muirhead, Koji Mukai, Susan Elizabeth Mullally, Fergal Mullally, Catriona Murray, Norio Narita, Enric Palle, Daria Pidhorodetska, David Quinn, Howard Relles, Stephen A Rinehart, Matthew Ritsko, Joseph E. Rodriguez, Pamela Rowden, Jason F. Rowe, Daniel Sebastian, Ramotholo Sefako, Sahar Shahaf, Avi Shporer, Naylynn Tañón Reyes, Peter Gregory Tenenbaum, Eric Bi-wen Ting, Joseph D Twicken, Gerard T. van Belle, Laura Vega, Jeffrey Francis Volosin, Lucianne M Walkowicz, and Allison Youngblood
Subjects: Astronomy
Abstract: We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-size planets transiting L98-59 (TOI-175, TIC 307210830)—a bright M dwarf at a distance of 10.6 pc. Using the Gaia-measured distance and broadband photometry, we find that the host star is an M3 dwarf. Combined with the TESS transits from three sectors, the corresponding stellar parameters yield planet radii ranging from 0.8 R⊕ to 1.6 R⊕. All three planets have short orbital periods, ranging from 2.25 to 7.45 days with the outer pair just wide of a 2:1 period resonance. Diagnostic tests produced by the TESS Data Validation Report and the vetting package DAVE rule out common false-positive sources. These analyses, along with dedicated follow-up and the multiplicity of the system, lend confidence that the observed signals are caused by planets transiting L 98-59 and are not associated with other sources in the field. The L 98-59 system is interesting for a number of reasons: the host star is bright (V =11.7 mag, K = 7.1 mag) and the planets are prime targets for further follow-up observations including precision radial-velocity mass measurements and future transit spectroscopy with the James Webb Space Telescope; the near-resonant configuration makes the system a laboratory to study planetary system dynamical evolution; and three planets of relatively similar size in the same system present an opportunity to study terrestrial planets where other variables (age, metallicity, etc.) can be held constant. L 98-59 will be observed in four more TESS sectors, which will provide a wealth of information on the three currently known planets and have the potential to reveal additional planets in the system.
Published: 2019
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21. TOI-530b: a giant planet transiting an M-dwarf detected by TESS

Author: Tianjun Gan, Zitao Lin, Sharon Xuesong Wang, Shude Mao, Pascal Fouqué, Jiahao Fan, Megan Bedell, Keivan G Stassun, Steven Giacalone, Akihiko Fukui, Felipe Murgas, David R Ciardi, Steve B Howell, Karen A Collins, Avi Shporer, Luc Arnold, Thomas Barclay, David Charbonneau, Jessie Christiansen, Ian J M Crossfield, Courtney D Dressing, Ashley Elliott, Emma Esparza-Borges, Phil Evans, Crystal L Gnilka, Erica J Gonzales, Andrew W Howard, Keisuke Isogai, Kiyoe Kawauchi, Seiya Kurita, Beibei Liu, John H Livingston, Rachel A Matson, Norio Narita, Enric Palle, Hannu Parviainen, Benjamin V Rackham, David R Rodriguez, Mark Rose, Alexander Rudat, Joshua E Schlieder, Nicholas J Scott, Michael Vezie, George R Ricker, Roland Vanderspek, David W Latham, Sara Seager, Joshua N Winn, Jon M Jenkins, Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: detection, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, planets and satellites: gaseous planets, Astrophysics - Solar and Stellar Astrophysics, stars: low-mass, [SDU]Sciences of the Universe [physics], Space and Planetary Science, TOI 530, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, planets and satellites: individual: TIC 387690507, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of TOI-530b, a transiting giant planet around an M0.5V dwarf, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located at a distance of $147.7\pm0.6$ pc with a radius of $R_{\ast}=0.54\pm0.03\ R_{\odot}$ and a mass of $M_{\ast}=0.53\pm0.02\ M_{\odot}$. We verify the planetary nature of the transit signals by combining ground-based multi-wavelength photometry, high resolution spectroscopy from SPIRou as well as high-angular-resolution imaging. With $V=15.4$ mag, TOI-530b is orbiting one of the faintest stars accessible by ground-based spectroscopy. Our model reveals that TOI-530b has a radius of $0.83\pm0.05\ R_{J}$ and a mass of $0.4\pm0.1\ M_{J}$ on a 6.39-d orbit. TOI-530b is the sixth transiting giant planet hosted by an M-type star, which is predicted to be infrequent according to core accretion theory, making it a valuable object to further study the formation and migration history of similar planets. We discuss the potential formation channel of such systems., Comment: 17 pages, 12 figures, 8 tables, accepted for publication by MNRAS
Published: 2021

22. The Pre-He White Dwarf in the Post-mass Transfer Binary EL CVn

Author: Luqian 璐茜 Wang 王, Douglas R. Gies, Kathryn V. Lester, Zhao Guo, Rachel A. Matson, Geraldine J. Peters, Vik S. Dhillon, Tim Butterley, Stuart P. Littlefair, Richard W. Wilson, and Pierre F. L. Maxted
Published: 2019
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23. Determining Which Binary Component Hosts the TESS Transiting Planet

Author: Kathryn V. Lester, Steve B. Howell, David R. Ciardi, and Rachel A. Matson
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: The NASA TESS mission has discovered many transiting planets orbiting bright nearby stars, and high-resolution imaging studies have revealed that a number of these exoplanet hosts reside in binary or multiple star systems. In such systems, transit observations alone cannot determine which star in the binary system actually hosts the orbiting planet. The knowledge of which star the planet orbits is necessary for determining accurate physical properties for the planet, especially its true radius and mean bulk density. We derived the mean stellar densities for the components of 23 binary systems using the light curve transit shape and the binary flux ratio from speckle imaging, then tested the consistency with stellar models to determine which component is the host star. We found that 70% of the TESS transiting planets in our sample orbit the primary star., Accepted for publication in AJ
Published: 2022

24. TOI-1842b: A Transiting Warm Saturn Undergoing Reinflation around an Evolving Subgiant

Author: Robert A. Wittenmyer, Jake T. Clark, Trifon Trifonov, Brett C. Addison, Duncan J. Wright, Keivan G. Stassun, Jonathan Horner, Nataliea Lowson, John Kielkopf, Stephen R. Kane, Peter Plavchan, Avi Shporer, Hui Zhang, Brendan P. Bowler, Matthew W. Mengel, Jack Okumura, Markus Rabus, Marshall C. Johnson, Daniel Harbeck, René Tronsgaard, Lars A. Buchhave, Karen A. Collins, Kevin I. Collins, Tianjun Gan, Eric L. N. Jensen, Steve B. Howell, E. Furlan, Crystal L. Gnilka, Kathryn V. Lester, Rachel A. Matson, Nicholas J. Scott, George R. Ricker, Roland Vanderspek, David W. Latham, S. Seager, Joshua N. Winn, Jon M. Jenkins, Alexander Rudat, Elisa V. Quintana, David R. Rodriguez, Douglas A. Caldwell, Samuel N. Quinn, Zahra Essack, and Luke G. Bouma
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: The imminent launch of space telescopes designed to probe the atmospheres of exoplanets has prompted new efforts to prioritise the thousands of transiting planet candidates for follow-up characterisation. We report the detection and confirmation of TOI-1842b, a warm Saturn identified by TESS and confirmed with ground-based observations from Minerva-Australis, NRES, and the Las Cumbres Observatory Global Telescope. This planet has a radius of $1.04^{+0.06}_{-0.05}\,R_{Jup}$, a mass of $0.214^{+0.040}_{-0.038}\,M_{Jup}$, an orbital period of $9.5739^{+0.0002}_{-0.0001}$ days, and an extremely low density ($\rho$=0.252$\pm$0.091 g cm$^{-3}$). TOI-1842b has among the best known combinations of large atmospheric scale height (893 km) and host-star brightness ($J=8.747$ mag), making it an attractive target for atmospheric characterisation. As the host star is beginning to evolve off the main sequence, TOI-1842b presents an excellent opportunity to test models of gas giant re-inflation. The primary transit duration of only 4.3 hours also makes TOI-1842b an easily-schedulable target for further ground-based atmospheric characterisation., Comment: Accepted for publication in AJ
Published: 2022

25. A Transiting, Temperate Mini-Neptune Orbiting the M Dwarf TOI-1759 Unveiled by TESS

Author: Néstor Espinoza, Enric Pallé, Jonas Kemmer, Rafael Luque, José A. Caballero, Carlos Cifuentes, Enrique Herrero, Víctor J. Sánchez Béjar, Stephan Stock, Karan Molaverdikhani, Giuseppe Morello, Diana Kossakowski, Martin Schlecker, Pedro J. Amado, Paz Bluhm, Miriam Cortés-Contreras, Thomas Henning, Laura Kreidberg, Martin Kürster, Marina Lafarga, Nicolas Lodieu, Juan Carlos Morales, Mahmoudreza Oshagh, Vera M. Passegger, Alexey Pavlov, Andreas Quirrenbach, Sabine Reffert, Ansgar Reiners, Ignasi Ribas, Eloy Rodríguez, Cristina Rodríguez López, Andreas Schweitzer, Trifon Trifonov, Priyanka Chaturvedi, Stefan Dreizler, Sandra V. Jeffers, Adrian Kaminski, María José López-González, Jorge Lillo-Box, David Montes, Grzegorz Nowak, Santos Pedraz, Siegfried Vanaverbeke, Maria R. Zapatero Osorio, Mathias Zechmeister, Karen A. Collins, Eric Girardin, Pere Guerra, Ramon Naves, Ian J. M. Crossfield, Elisabeth C. Matthews, Steve B. Howell, David R. Ciardi, Erica Gonzales, Rachel A. Matson, Charles A. Beichman, Joshua E. Schlieder, Thomas Barclay, Michael Vezie, Jesus Noel Villaseñor, Tansu Daylan, Ismael Mireies, Diana Dragomir, Joseph D. Twicken, Jon Jenkins, Joshua N. Winn, David Latham, George Ricker, and Sara Seager
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Astrofísica, Exoplanet astronomy, Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.-- Full list of authors: Espinoza, Néstor; Pallé, Enric; Kemmer, Jonas; Luque, Rafael; Caballero, José A.; Cifuentes, Carlos; Herrero, Enrique; Sánchez Béjar, Víctor J.; Stock, Stephan; Molaverdikhani, Karan; Morello, Giuseppe; Kossakowski, Diana; Schlecker, Martin; Amado, Pedro J.; Bluhm, Paz; Cortés-Contreras, Miriam; Henning, Thomas; Kreidberg, Laura; Kürster, Martin; Lafarga, Marina; Lodieu, Nicolas; Morales, Juan Carlos; Oshagh, Mahmoudreza; Passegger, Vera M.; Pavlov, Alexey; Quirrenbach, Andreas; Reffert, Sabine; Reiners, Ansgar; Ribas, Ignasi; Rodríguez, Eloy; López, Cristina Rodríguez; Schweitzer, Andreas; Trifonov, Trifon; Chaturvedi, Priyanka; Dreizler, Stefan; Jeffers, Sandra V.; Kaminski, Adrian; López-González, María José; Lillo-Box, Jorge; Montes, David; Nowak, Grzegorz; Pedraz, Santos; Vanaverbeke, Siegfried; Zapatero Osorio, Maria R.; Zechmeister, Mathias; Collins, Karen A.; Girardin, Eric; Guerra, Pere; Naves, Ramon; Crossfield, Ian J. M.; Matthews, Elisabeth C.; Howell, Steve B.; Ciardi, David R.; Gonzales, Erica; Matson, Rachel A.; Beichman, Charles A.; Schlieder, Joshua E.; Barclay, Thomas; Vezie, Michael; Villaseñor, Jesus Noel; Daylan, Tansu; Mireies, Ismael; Dragomir, Diana; Twicken, Joseph D.; Jenkins, Jon; Winn, Joshua N.; Latham, David; Ricker, George; Seager, Sara., We report the discovery and characterization of TOI-1759 b, a temperate (400 K) sub-Neptune-sized exoplanet orbiting the M dwarf TOI-1759 (TIC 408636441). TOI-1759 b was observed by TESS to transit in Sectors 16, 17, and 24, with only one transit observed per sector, creating an ambiguity regarding the orbital period of the planet candidate. Ground-based photometric observations, combined with radial-velocity measurements obtained with the CARMENES spectrograph, confirm an actual period of 18.85019 ± 0.00014 days. A joint analysis of all available photometry and radial velocities reveals a radius of 3.17 ± 0.10 R⊕ and a mass of 10.8 ± 1.5 M⊕. Combining this with the stellar properties derived for TOI-1759 (R⋆ = 0.597 ± 0.015 R⊙; M⋆ = 0.606 ± 0.020 M⊙; Teff = 4065 ± 51 K), we compute a transmission spectroscopic metric (TSM) value of over 80 for the planet, making it a good target for transmission spectroscopy studies. TOI-1759 b is among the top five temperate, small exoplanets (Teq < 500 K, Rp < 4 R⊕) with the highest TSM discovered to date. Two additional signals with periods of 80 days and >200 days seem to be present in our radial velocities. While our data suggest both could arise from stellar activity, the later signal's source and periodicity are hard to pinpoint given the ∼200 days baseline of our radial-velocity campaign with CARMENES. Longer baseline radial-velocity campaigns should be performed in order to unveil the true nature of this long-period signal. © 2022. The Author(s). Published by the American Astronomical Society., CARMENES is an instrument at the Centro Astronómico Hispano-Alemán (CAHA) at Calar Alto (Almería, Spain), operated jointly by the Junta de Andalucía and the Instituto de Astrofísica de Andalucía (CSIC). CARMENES was funded by the Max-Planck-Gesellschaft (MPG), the Consejo Superior de Investigaciones Científicas (CSIC), the Ministerio de Economía y Competitividad (MINECO), and the European Regional Development Fund (ERDF) through projects FICTS-2011-02, ICTS-2017-07-CAHA-4, and CAHA16-CE-3978, and the members of the CARMENES Consortium (Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Andalucía, Landessternwarte Königstuhl, Institut de Ciëncies de l'Espai, Institut für Astrophysik Göttingen, Universidad Complutense de Madrid, Thüringer Landessternwarte Tautenburg, Instituto de Astrofísica de Canarias, Hamburger Sternwarte, Centro de Astrobiología, and Centro Astronómico Hispano-Alemán), with additional contributions by the MINECO, the Deutsche Forschungsgemeinschaft through the Major Research Instrumentation Programme and Research Unit FOR2544 "Blue Planets around Red Stars," the Klaus Tschira Stiftung, the states of Baden-Württemberg and Niedersachsen, and by the Junta de Andalucía. This work was based on data from the CARMENES data archive at CAB (CSIC-INTA). We acknowledge financial support from the Agencia Estatal de Investigación of the Ministerio de Ciencia, Innovación y Universidades and the ERDF through projects PID2019-109522GB-C5[1:4], PGC2018-098153-B-C33, AYA2018-84089, PID2019-107061GB-C64, PID2019-110689RB-100, AYA2016-79425-C3-1/2/3-P, and BES-2017-080769, and the Centre of Excellence "Severo Ochoa" and "María de Maeztu" awards to the Instituto de Astrofísica de Canarias (CEX2019-000920-S), Instituto de Astrofísica de Andalucía (SEV-2017-0709), and Centro de Astrobiología (MDM-2017-0737), NASA (NNX17AG24G), and the Generalitat de Catalunya/CERCA program. Data were partly collected with the 90 cm telescope at the Sierra Nevada Observatory (SNO) operated by the Instituto de Astrofí fica de Andalucí a (IAA, CSIC). We acknowledge the telescope operators from the Sierra Nevada Observatory for their support. G.M. has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 895525. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products.
Published: 2022

26. TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet

Author: Andrés Jordán, Sara Seager, Brett C. Addison, Maximilian N. Günther, Monika Lendl, Jack Okumura, Jorge Lillo-Box, Jon M. Jenkins, Roland Vanderspek, C. G. Tinney, Benjamin J. Fulton, Peter J. Wheatley, Erik A. Petigura, Beth A. Henderson, C. Stibbard, P. Figueira, Rafael Brahm, Eric L. N. Jensen, Michael Reefe, Cesar Briceno, Chris Stockdale, S. Hojjatpanah, Farisa Y. Morales, Alexis M. S. Smith, Caroline Dorn, Thomas Henning, Vardan Adibekyan, George W. King, Lauren M. Weiss, David R. Ciardi, Howard Isaacson, Richard P. Schwarz, Thomas Barclay, Stephen R. Kane, Keivan G. Stassun, David W. Latham, Malcolm Fridlund, Jack S. Acton, Ravit Helled, Sharon X. Wang, John Berberian, Joseph D. Twicken, J. F. Otegi, David R. Anderson, Sarah L. Casewell, Elise Furlan, Elisabeth Matthews, Johanna Teske, Rodrigo F. Díaz, Samuel Gill, Daniel Bayliss, Ian Crossfield, Peter Plavchan, Matthew W. Mengel, Joshua E. Schlieder, John F. Kielkopf, Stéphane Udry, E. Delgado Mena, H. P. Osborn, Avi Shporer, R. Cloutier, J. Villasenor, Duncan J. Wright, E. Gaidos, A. Osborn, K. I. Collins, Angelle Tanner, Nicholas M. Law, Björn Benneke, Joshua N. Winn, Fei Dai, Nicholas J. Scott, Erica J. Gonzales, Courtney D. Dressing, Sarah Ballard, Don Pollacco, Coel Hellier, Michael R. Goad, David J. Armstrong, Varoujan Gorjian, Paula Sarkis, Richard C. Kidwell, F. Zohrabi, Nuno C. Santos, David Barrado, Matthew R. Burleigh, Sergio Hoyer, Claire Geneser, Christopher J. Burke, Richard G. West, James McCormac, P. A. Strøm, Daniel Huber, Aleisha Hogan, Paul Robertson, Natalie M. Batalha, Edward M. Bryant, Liam Raynard, Karen A. Collins, Robert A. Wittenmyer, Mark E. Rose, Rachel A. Matson, Steve B. Howell, James S. Jenkins, Jose I. Vines, S. C. C. Barros, Néstor Espinoza, B. Cale, Andrew W. Howard, Diana Dragomir, Alexandre Santerne, M. Lund, Olivier Demangeon, Brendan P. Bowler, Benjamin F. Cooke, Xavier Dumusque, Andrew W. Mann, Hui Zhang, Carl Ziegler, Arpita Roy, Rosanna H. Tilbrook, Sérgio F. Sousa, George R. Ricker, Jonathan Horner, Elisa V. Quintana, Thiam-Guan Tan, Louise D. Nielsen, François Bouchy, University of New South Wales [Sydney] (UNSW), McDonald Observatory, University of Texas at Austin [Austin], Leiden Observatory [Leiden], Universiteit Leiden, Chalmers University of Technology [Gothenburg, Sweden], NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Instituto de Astrofísica e Ciências do Espaço (IASTRO), Center for Space Research [Cambridge] (CSR), Massachusetts Institute of Technology (MIT), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Département de Physique [Montréal], Université de Montréal (UdeM), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Leicester], University of Leicester, Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), Optimisation - Système - Energie (GEPEA-OSE), Laboratoire de génie des procédés - environnement - agroalimentaire (GEPEA), Institut Universitaire de Technologie - Nantes (IUT Nantes), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut Universitaire de Technologie Saint-Nazaire (IUT Saint-Nazaire), Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut Universitaire de Technologie - La Roche-sur-Yon (IUT La Roche-sur-Yon), Université de Nantes (UN)-Institut Universitaire de Technologie - Nantes (IUT Nantes), Université de Nantes (UN), Institut für Virologie, Philipps University, MIT Kavli Institute for Astrophysics and Space Research, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Department of Geology and Geophysics [Mānoa], University of Hawai‘i [Mānoa] (UHM), Universität Zürich [Zürich] = University of Zurich (UZH), Department of Earth and Planetary Science [UC Berkeley] (EPS), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Universidad de Chile = University of Chile [Santiago] (UCHILE), Pontificia Universidad Católica de Chile (UC), University of Louisville, Austrian Academy of Sciences (OeAW), Lund University [Lund], University of Warwick [Coventry], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), German Aerospace Center (DLR), Swiss Bee Research Centre, Centre for Medical Image Computing (CMIC), and University College of London [London] (UCL)
Subjects: (TOI-431, planets and satellites: detection, Fundamental Parameters, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], (TOI-431, TIC 31374837), FOS: Physical sciences, Individual, Astrophysics, Q1, 01 natural sciences, Neptune, Planet, QB460, 0103 physical sciences, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, QB600, QC, 0105 earth and related environmental sciences, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Super-Earth, Astronomy and Astrophysics, Planets and Satellites, Radius, Light curve, Exoplanet, Radial velocity, Photometry (astronomy), Detection, 13. Climate action, Space and Planetary Science, planets and satellites: individual: (TOI-431, TIC 31374837), Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the bright (V$_{mag} = 9.12$), multi-planet system TOI-431, characterised with photometry and radial velocities. We estimate the stellar rotation period to be $30.5 \pm 0.7$ days using archival photometry and radial velocities. TOI-431b is a super-Earth with a period of 0.49 days, a radius of 1.28 $\pm$ 0.04 R$_{\oplus}$, a mass of $3.07 \pm 0.35$ M$_{\oplus}$, and a density of $8.0 \pm 1.0$ g cm$^{-3}$; TOI-431d is a sub-Neptune with a period of 12.46 days, a radius of $3.29 \pm 0.09$ R$_{\oplus}$, a mass of $9.90^{+1.53}_{-1.49}$ M$_{\oplus}$, and a density of $1.36 \pm 0.25$ g cm$^{-3}$. We find a third planet, TOI-431c, in the HARPS radial velocity data, but it is not seen to transit in the TESS light curves. It has an $M \sin i$ of $2.83^{+0.41}_{-0.34}$ M$_{\oplus}$, and a period of 4.85 days. TOI-431d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterisation, while the super-Earth TOI-431b may be a stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431b is a prime TESS discovery for the study of rocky planet phase curves., Comment: 21 pages, 11 figures, 3 appendices, accepted for publication in MNRAS
Published: 2021

27. TOI-674b: An oasis in the desert of exo-Neptunes transiting a nearby M dwarf

Author: Xavier Bonfils, Michael W. Werner, Nicola Astudillo-Defru, Jon M. Jenkins, George R. Ricker, Ian J. M. Crossfield, Eric L. N. Jensen, David R. Ciardi, Emmanuel Jehin, Judith Korth, David W. Latham, Farisa Y. Morales, Ismael Mireles, Keivan G. Stassun, Étienne Artigau, Rodrigo F. Díaz, J. Orell-Miquel, Pedro Figueira, Stéphane Udry, René Doyon, X. Delfosse, Jack J. Lissauer, Francesco Pepe, Damien Ségransan, Nuno C. Santos, Christophe Lovis, Peter Tenenbaum, Elisa V. Quintana, Björn Benneke, Rachel A. Matson, Jose-Manuel Almenara, Felipe Murgas, Douglas A. Caldwell, Kevin I. Collins, Phil Evans, C. E. Brasseur, Stephen R. Kane, François Bouchy, David Charbonneau, G. Morello, Roland Vanderspek, Charles Beichman, Elisabeth Matthews, T. Forveille, Khalid Barkaoui, Sara Seager, Diana Dragomir, Erica J. Gonzales, Robert F. Goeke, G. Gaisne, Joshua E. Schlieder, John H. Livingston, Natalia Guerrero, Claudio Melo, Alan M. Levine, Joshua N. Winn, Steve B. Howell, Michaël Gillon, Francisco J. Pozuelos, Jason D. Eastman, Varoujan Gorjian, Karen A. Collins, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Departamento de Matemática y Fı́sica Aplicadas [Concepcion] (DMFA), Universidad Católica de la Santísima Concepción (UCSC), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), and Children's Hospital of Leeds
Subjects: 010504 meteorology & atmospheric sciences, GASEOUS PLANETS [PLANETS AND SATELLITES], FOS: Physical sciences, RADIAL VELOCITIES [TECHNIQUES], Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, purl.org/becyt/ford/1 [https], Planet, 0103 physical sciences, GENERAL [PLANETS AND SATELLITES], PLANETARY SYSTEMS, 010303 astronomy & astrophysics, INDIVIDUAL: TOI-674 [STARS], Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Orbital elements, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Radius, purl.org/becyt/ford/1.3 [https], PHOTOMETRIC [TECHNIQUES], Light curve, Orbital period, Exoplanet, Radial velocity, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract: We use TESS, Spitzer, ground-based light curves and HARPS spectrograph radial velocity measurements to establish the physical properties of the transiting exoplanet candidate TOI-674b. We perform a joint fit of the light curves and radial velocity time series to measure the mass, radius, and orbital parameters of the candidate. We confirm and characterize TOI-674b, a low-density super-Neptune transiting a nearby M dwarf. The host star (TIC 158588995, $V = 14.2$ mag, $J = 10.3$ mag) is characterized by its M2V spectral type with $\mathrm{M}_\star=0.420\pm 0.010$ M$_\odot$, $\mathrm{R}_\star = 0.420\pm 0.013$ R$_\odot$, and $\mathrm{T}_{\mathrm{eff}} = 3514\pm 57$ K, and is located at a distance $d=46.16 \pm 0.03$ pc. Combining the available transit light curves plus radial velocity measurements and jointly fitting a circular orbit model, we find an orbital period of $1.977143 \pm 3\times 10^{-6}$ days, a planetary radius of $5.25 \pm 0.17$ $\mathrm{R}_\oplus$, and a mass of $23.6 \pm 3.3$ $\mathrm{M}_\oplus$ implying a mean density of $\rho_\mathrm{p} = 0.91 \pm 0.15$ [g cm$^{-3}$]. A non-circular orbit model fit delivers similar planetary mass and radius values within the uncertainties. Given the measured planetary radius and mass, TOI-674b is one of the largest and most massive super-Neptune class planets discovered around an M type star to date. It is also a resident of the so-called Neptunian desert and a promising candidate for atmospheric characterisation using the James Webb Space Telescope., Comment: 22 pages, 16 figures. Accepted for publication in A&A
Published: 2021

28. Twin High-Resolution, High-Speed Imagers for the Gemini Telescopes: Instrument Description and Science Verification Results

Author: Emmett A. Quigley, Nicholas J. Scott, Andrew W. Stephens, Rachel A. Matson, Elise Furlan, Ricardo Salinas, Steve B. Howell, Mark E. Everett, David R. Ciardi, Crystal L. Gnilka, Dave Mills, and Elliott P. Horch
Subjects: Physics, astronomical instrumentation, QC801-809, multiple stars, Astronomy, Geophysics. Cosmic physics, Astronomy and Astrophysics, Field of view, QB1-991, optical astronomy, Position angle, Exoplanet, Stars, Speckle pattern, Limiting magnitude, speckle interfcromctry, Speckle imaging, ground-based astronomy, Transit (satellite)
Abstract: Two new imaging instruments, ‘Alopeke and Zorro, were designed, built, and commissioned at the Gemini-North and Gemini-South telescopes in 2018 and 2019, respectively. Here we describe them and present the results from over a year of operation. The two identical instruments are based on the legacy of the DSSI (Differential Speckle Survey Instrument) instrument, successfully used for years at the WIYN and the Gemini telescopes in Hawaii and Chile. ‘Alopeke and Zorro are dual-channel imagers having both speckle (6.7″) and “wide-field” (∼1 arcminute) field-of-view options. They were built to primarily perform speckle interferometry providing diffraction-limited imagery at optical wavebands, yielding pixel scale uncertainties of ±0.21 mas, position angle uncertainties of ±0.7◦, and photometric uncertainties of Δm ± 0.02–0.04 magnitudes (for the blue and red channels, respectively) when run through the standard data reduction pipeline. One of their main scientific roles is the validation and characterization of exoplanets and their host stars as discovered by transit surveys such as the NASA Kepler, K2, and TESS missions. The limiting magnitude for speckle observations at Gemini can be quite faint (r ∼18 in good observing conditions) but typically the observed targets are brighter. The instruments can also function as conventional CCD imagers providing a 1 arc-minute field of view and allowing simultaneous two-color, high-speed time-series operation. These resident visitor instruments are remotely operable and are available for use by the community via the peer-reviewed proposal process.
Published: 2021

29. Speckle Observations of TESS Exoplanet Host Stars. II. Stellar Companions at 1–1000 au and Implications for Small Planet Detection

Author: Elise Furlan, Nicholas J. Scott, Lea A. Hirsch, Steve B. Howell, Zachary Hartman, Kathryn V. Lester, Mark E. Everett, Rachel A. Matson, Crystal L. Gnilka, and David R. Ciardi
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Mass ratio, Orbital period, Exoplanet, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, Primary (astronomy), Binary star, Astrophysics::Solar and Stellar Astrophysics, Speckle imaging, Astrophysics::Earth and Planetary Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present high angular resolution imaging observations of 517 host stars of TESS exoplanet candidates using the `Alopeke and Zorro speckle cameras at Gemini North and South. The sample consists mainly of bright F, G, K stars at distances of less than 500 pc. Our speckle observations span angular resolutions of ~20 mas out to 1.2 arcsec, yielding spatial resolutions of, Accepted to AJ
Published: 2021

30. Ultra-short-period Planets in K2. III. Neighbors are Common with 13 New Multiplanet Systems and 10 Newly Validated Planets in Campaigns 0–8 and 10

Author: Prasanna Jayanthi, Steve B. Howell, Carl Ziegler, David R. Ciardi, Nicholas J. Scott, Brian Jackson, Rachel A. Matson, Michael Endl, Samantha Johnson, Mark E. Everett, Ciera Partyka-Worley, Sevio M. Stanton, William D. Cochran, E. R. Adams, Joshua E. Schlieder, Elise Furlan, and Phillip J. MacQueen
Subjects: Physics, Geophysics, Space and Planetary Science, Planet, Earth and Planetary Sciences (miscellaneous), Astronomy and Astrophysics, Period (music), Astrobiology
Abstract: Using the EVEREST photometry pipeline, we have identified 74 candidate ultra-short-period planets (USPs; orbital period P < 1 day) in the first half of the K2 data (Campaigns 0–8 and 10). Of these, 33 candidates have not previously been reported. A systematic search for additional transiting planets found 13 new multiplanet systems containing a USP, doubling the number known and representing a third (32%) of USPs in our sample from K2. We also identified 30 companions, which have periods from 1.4 to 31 days (median 5.5 days). A third (36 of 104) of the candidate USPs and companions have been statistically validated or confirmed in this work, 10 for the first time, including 7 USPs. Almost all candidates, and all validated planets, are small (radii R p ≤ 3 R ⊕) with a median radius of R p = 1.1 R ⊕; the validated and confirmed USP candidates have radii between 0.4 R ⊕ and 2.4 R ⊕ and periods from P = 0.18 to 0.96 days. The lack of candidate (a) ultra-hot-Jupiter (R p > 10 R ⊕) and (b) short-period-desert (3 ≤ R p ≤ 10 R ⊕) planets suggests that both populations are rare, although our survey may have missed some of the very deepest transits. These results also provide strong evidence that we have not reached a lower limit on the distribution of planetary radius values for planets at close proximity to a star and suggest that additional improvements in photometry techniques would yield yet more USPs. The large fraction of USPs in known multiplanet systems supports origins models that involve dynamical interactions with exterior planets coupled to tidal decay of the USP orbits.
Published: 2021

31. TOI-220 b: a warm sub-Neptune discovered by TESS

Author: Petr Kabath, K. I. Collins, Florian Rodler, Christopher Stockdale, Sara Seager, T. Lopez, S. Hojjatpanah, Steve B. Howell, S. Sabotta, Nuno C. Santos, David Barrado, Enric Palle, Jan Subjak, M. Esposito, John P. Doty, Rafael Luque, Artyom Aguichine, Karen A. Collins, Olivier Demangeon, Vincent Van Eylen, J. R. De Medeiros, M. Fridlund, N. Scott, Susan E. Mullally, E. Goffo, J. F. Otegi, D. W. Latham, Oscar Barragán, Jon M. Jenkins, Rodrigo F. Díaz, L. M. Serrano, Stéphane Udry, P. Figueira, A. P. Hatzes, Vardan Adibekyan, Davide Gandolfi, P. Cortés-Zuleta, W. Fong, J. Cabrera, Peter J. Wheatley, Seth Redfield, Sascha Grziwa, A. Santerne, Benjamin F. Cooke, Sergio Hoyer, L. Acuña, Daniel Bayliss, J. D. Twicken, S. G. Sousa, A. Osborn, Joshua N. Winn, P. A. Strøm, Hans J. Deeg, E. Delgado Mena, H. P. Osborn, William D. Cochran, Rachel A. Matson, Elise Furlan, Jorge Lillo-Box, P. T. Boyd, John H. Livingston, I. C. Leão, James A. G. Jackman, Edward M. Bryant, François Bouchy, Magali Deleuil, O. Mousis, Jose-Manuel Almenara, Carina M. Persson, Judith Korth, Roland Vanderspek, Louise D. Nielsen, B. L. Canto Martins, David J. Armstrong, Eric L. N. Jensen, Emil Knudstrup, D. A. Yahalomi, Jeffrey C. Smith, S. C. C. Barros, Xavier Dumusque, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Department of Brain and Behavioural Sciences, University of Pavia, European Southern Observatory (ESO), Instituto de Astrofísica e Ciências do Espaço (IASTRO), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto, Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Groupe de Recherche en Astronomie et Astrophysique du Languedoc (GRAAL), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astronomía y Física del Espacio [Buenos Aires] (IAFE), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad de Buenos Aires [Buenos Aires] (UBA), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Center for Space Research [Cambridge] (CSR), Massachusetts Institute of Technology (MIT), University of Warwick [Coventry], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Physics [Coventry], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Institute for Marine and Antarctic Studies [Horbat] (IMAS), University of Tasmania [Hobart, Australia] (UTAS), PSE-ENV/SEDRE/LETIS, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), European Southern Observatory [Santiago] (ESO), Thüringer Landessternwarte Tautenburg (TLS), Astronomical Institute of the Czech Academy of Sciences (ASU / CAS), Czech Academy of Sciences [Prague] (CAS), Universidad de Córdoba [Cordoba], Instituto de Astrofisica de Canarias (IAC), Wesleyan University, Departamento de Física e Astronomia [Porto] (DFA/FCUP), Faculdade de Ciências da Universidade do Porto (FCUP), Universidade do Porto-Universidade do Porto, Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Pavia = University of Pavia (UNIPV), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universidade do Porto = University of Porto, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Université de Genève = University of Geneva (UNIGE), Institute for Marine and Antarctic Studies [Hobart] (IMAS), Laboratoire d'étude et de recherche sur les transferts et les interactions dans les sous-sols (IRSN/PSE-ENV/SEDRE/LETIS), Service des déchets radioactifs et des transferts dans la géosphère (IRSN/PSE-ENV/SEDRE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Universidad de Córdoba = University of Córdoba [Córdoba], and Universidade do Porto = University of Porto-Universidade do Porto = University of Porto
Subjects: Dwarf star, Fundamental Parameters, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Individual, Astrophysics, Photometric, planets and satellites: individual: TYC 8897-01263-1, 01 natural sciences, techniques: photometric, Planet, Neptune, 0103 physical sciences, techniques: radial velocities, Radial Velocities, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, TYC 8897-01263-1, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy and Astrophysics, Planets and Satellites, Radius, Planetary system, Stars, Exoplanet, Techniques, Radial velocity, 13. Climate action, Space and Planetary Science, echniques: photometric, stars: fundamental parameters, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract: In this paper we report the discovery of TOI-220 $b$, a new sub-Neptune detected by the Transiting Exoplanet Survey Satellite (TESS) and confirmed by radial velocity follow-up observations with the HARPS spectrograph. Based on the combined analysis of TESS transit photometry and high precision radial velocity measurements we estimate a planetary mass of 13.8 $\pm$ 1.0 M$_{Earth}$ and radius of 3.03 $\pm$ 0.15 R$_{Earth}$, implying a bulk density of 2.73 $\pm$ 0.47 $\textrm{g cm}^{-3}$. TOI-220 $b$ orbits a relative bright (V=10.4) and old (10.1$\pm$1.4 Gyr) K dwarf star with a period of $\sim$10.69 d. Thus, TOI-220 $b$ is a new warm sub-Neptune with very precise mass and radius determinations. A Bayesian analysis of the TOI-220 $b$ internal structure indicates that due to the strong irradiation it receives, the low density of this planet could be explained with a steam atmosphere in radiative-convective equilibrium and a supercritical water layer on top of a differentiated interior made of a silicate mantle and a small iron core., Comment: Accepted for publication in MNRAS
Published: 2021

32. TOI-1231 b: A Temperate, Neptune-Sized Planet Transiting the Nearby M3 Dwarf NLTT 24399

Author: Wenceslas Marie-Sainte, Xavier Bonfils, Ian J. M. Crossfield, Christopher J. Burke, François-Xavier Schmider, Fabo Feng, Stephen A. Shectman, Antonio García Muñoz, Tansu Daylan, Elisabeth Matthews, Keivan G. Stassun, Diana Dragomir, Zachory K. Berta-Thompson, Abdelkrim Agabi, Rachel A. Matson, Nicolas Crouzet, Bill Wohler, Roland Vanderspek, Jennifer Burt, Johanna Teske, Sara Seager, C. E. Brasseur, David Charbonneau, Djamel Mékarnia, George R. Ricker, Amaury H. M. J. Triaud, Chelsea X. Huang, John McCann, Joshua Pepper, Jason D. Eastman, Allison Youngblood, Jeffrey D. Crane, Eric E. Mamajek, Lyu Abe, Karen A. Collins, Carl Ziegler, Tristan Guillot, Laura Kreidberg, Paul Mollière, David R. Ciardi, Daniel J. Stevens, Marion Cointepas, David W. Latham, Richard P. Schwarz, Andrew W. Mann, Joshua E. Schlieder, Joshua N. Winn, Georgina Dransfield, Elise Furlan, Eric L. N. Jensen, Steven Villanueva, Joseph E. Rodriguez, Jon M. Jenkins, Steve B. Howell, Sharon X. Wang, Arvind F. Gupta, Nicholas M. Law, Nic Scott, Samuel Halverson, R. Paul Butler, J. M. Almenara, Thomas Barclay, MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology (MIT), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Technische Universität Berlin (TU), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Smithsonian Institution-Harvard University [Cambridge], Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Radial velocity (1332), FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, law.invention, 010309 optics, Telescope, Neptune, law, Planet, Observatory, 0103 physical sciences, Transit photometry (1709), Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Exoplanets (498), Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Orbital period, Exoplanet, Radial velocity, Planetary science, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Planetary system formation (1257), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of a transiting, temperate, Neptune-sized exoplanet orbiting the nearby ($d$ = 27.5 pc), M3V star TOI-1231 (NLTT 24399, L 248-27, 2MASS J10265947-5228099). The planet was detected using photometric data from the Transiting Exoplanet Survey Satellite and followed up with observations from the Las Cumbres Observatory and the Antarctica Search for Transiting ExoPlanets program. Combining the photometric data sets, we find that the newly discovered planet has a radius of 3.65$^{+0.16}_{-0.15}$ R$_{\oplus}$, and an orbital period of 24.246 days. Radial velocity measurements obtained with the Planet Finder Spectrograph on the Magellan Clay telescope confirm the existence of the planet and lead to a mass measurement of 15.5$\pm$3.3 M$_{\oplus}$. With an equilibrium temperature of just 330K TOI-1231 b is one of the coolest small planets accessible for atmospheric studies thus far, and its host star's bright NIR brightness (J=8.88, K$_{s}$=8.07) make it an exciting target for HST and JWST. Future atmospheric observations would enable the first comparative planetology efforts in the 250-350 K temperature regime via comparisons with K2-18 b. Furthermore, TOI-1231's high systemic radial velocity (70.5 k\ms) may allow for the detection of low-velocity hydrogen atoms escaping the planet by Doppler shifting the H I Ly-alpha stellar emission away from the geocoronal and ISM absorption features., 20 pages, 9 figures. Accepted for publication in The Astronomical Journal
Published: 2021

33. The TESS-Keck Survey. II. An Ultra-short-period Rocky Planet and Its Siblings Transiting the Galactic Thick-disk Star TOI-561

Author: Phil Evans, Alexander Chaushev, Enric Palle, Karen A. Collins, Zachary R. Claytor, Ashley Chontos, Molly R. Kosiarek, John M. Brewer, Daniel Huber, Hannu Parviainen, Ian Crossfield, Thiam-Guan Tan, Felipe Murgas, Paul Robertson, Joseph M. Akana Murphy, George R. Ricker, J. Lubin, Richard P. Schwarz, Judah Van Zandt, Jessie L. Christiansen, Joshua E. Schlieder, Charles Beichman, Jack S. Acton, Lee J. Rosenthal, Rachel A. Matson, Stephen R. Kane, Mason G. MacDougall, S. Giacalone, Philipp Eigmüller, Corey Beard, Nicholas M. Law, Arpita Roy, Fei Dai, Erik A. Petigura, Edward M. Bryant, Norio Narita, Howard Isaacson, Teo Mocnik, Sara Seager, Cesar Briceno, Michael B. Lund, Keivan G. Stassun, Eric L. N. Jensen, Erica J. Gonzales, Michelle L. Hill, K. I. Collins, Elisabeth Matthews, Lauren M. Weiss, David R. Ciardi, Paul A. Dalba, Samuel Gill, Andrew W. Howard, Carl Ziegler, Andrew W. Mann, Courtney D. Dressing, Joseph D. Twicken, Steve B. Howell, Ryan A. Rubenzahl, Jon M. Jenkins, Benjamin J. Fulton, Natalie M. Batalha, Akihiko Fukui, Aida Behmard, and Joshua N. Winn
Subjects: 010504 meteorology & atmospheric sciences, Exoplanet astronomy, Exoplanet evolution, Population, FOS: Physical sciences, Astrophysics, 01 natural sciences, Photometry (optics), Exoplanet formation, Planet, Observatory, 0103 physical sciences, Thick disk, Exoplanet detection methods, education, 010303 astronomy & astrophysics, Exoplanet systems, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, Exoplanets, Astronomy and Astrophysics, Planetary system, Astrophysics - Astrophysics of Galaxies, Exoplanet, Exoplanet structure, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Terrestrial planet, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of TOI-561, a multi-planet system in the galactic thick disk that contains a rocky, ultra-short period planet (USP). This bright ($V=10.2$) star hosts three small transiting planets identified in photometry from the NASA TESS mission: TOI-561 b (TOI-561.02, P=0.44 days, $R_b = 1.45\pm0.11\,R_\oplus$), c (TOI-561.01, P=10.8 days, $R_c=2.90\pm0.13\,R_\oplus$), and d (TOI-561.03, P=16.3 days, $R_d=2.32\pm0.16\,R_\oplus$). The star is chemically ([Fe/H]$=-0.41\pm0.05$, [$\alpha$/H]$=+0.23\pm0.05$) and kinematically consistent with the galactic thick disk population, making TOI-561 one of the oldest ($10\pm3\,$Gyr) and most metal-poor planetary systems discovered yet. We dynamically confirm planets b and c with radial velocities from the W. M. Keck Observatory High Resolution Echelle Spectrometer. Planet b has a mass and density of $3.2\pm0.8\,M_\oplus$ and $5.5^{+2.0}_{-1.6}\,$g$\,$cm$^{-3}$, consistent with a rocky composition. Its lower-than-average density is consistent with an iron-poor composition, although an Earth-like iron-to-silicates ratio is not ruled out. Planet c is $7.0\pm2.3\,M_\oplus$ and $1.6\pm0.6\,$g$\,$cm$^{-3}$, consistent with an interior rocky core overlaid with a low-mass volatile envelope. Several attributes of the photometry for planet d (which we did not detect dynamically) complicate the analysis, but we vet the planet with high-contrast imaging, ground-based photometric follow-up and radial velocities. TOI-561 b is the first rocky world around a galactic thick-disk star confirmed with radial velocities and one of the best rocky planets for thermal emission studies., Comment: Accepted at The Astronomical Journal; 25 pages, 10 figures
Published: 2021

34. Speckle Observations of TESS Exoplanet Host Stars: Understanding the Binary Exoplanet Host Star Orbital Period Distribution

Author: Rachel A. Matson, Elliott P. Horch, Mark E. Everett, John H. Livingston, David R. Ciardi, Nicholas J. Scott, Joshua N. Winn, and Steve B. Howell
Subjects: 010504 meteorology & atmospheric sciences, Stellar mass, FOS: Physical sciences, Binary number, Astrophysics, 01 natural sciences, Speckle pattern, Planet, 0103 physical sciences, Binary star, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Orbital period, Exoplanet, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present high-resolution speckle interferometric imaging observations of TESS exoplanet host stars using the NN-EXPLORE Exoplanet and Stellar Speckle Imager instrument at the 3.5 m WIYN telescope. Eight TESS objects of interest that were originally discovered by Kepler were previously observed using the Differential Speckle Survey Instrument. Speckle observations of 186 TESS stars were carried out, and 45 (24%) likely bound companions were detected. This is approximately the number of companions we would expect to observe given the established 46% binarity rate in exoplanet host stars. For the detected binaries, the distribution of stellar mass ratio is consistent with that of the standard Raghavan distribution and may show a decrease in high-q systems as the binary separation increases. The distribution of binary orbital periods, however, is not consistent with the standard Ragahavan model, and our observations support the premise that exoplanet-hosting stars with binary companions have, in general, wider orbital separations than field binaries. We find that exoplanet-hosting binary star systems show a distribution peaking near 100 au, higher than the 40–50 au peak that is observed for field binaries. This fact led to earlier suggestions that planet formation is suppressed in close binaries.
Published: 2021

35. TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley

Author: Gilbert A. Esquerdo, Walter Boschin, Lars A. Buchhave, Allyson Bieryla, Karen A. Collins, Eric L. N. Jensen, Nobuhiko Kusakabe, David F. Phillips, Chelsea X. Huang, Jack J. Lissauer, Steve B. Howell, Norio Narita, E. Girardin, Christopher A. Watson, Enric Palle, Damien Ségransan, R. D. Haywood, P. Guerra, David W. Latham, S. Giacalone, Jonathan Irwin, Avi Shporer, Keivan G. Stassun, Giampaolo Piotto, E. Esparza-Borges, Gloria Andreuzzi, Felipe Murgas, Marco Pedani, Francesco Pepe, Mercedes Lopez-Morales, Scott McDermott, Courtney D. Dressing, Robert Massey, Motohide Tamura, George R. Ricker, Annelies Mortier, Giuseppina Micela, Jessie L. Christiansen, Emilio Molinari, Pau Bosch-Cabot, Jon M. Jenkins, Roland Vanderspek, Aldo F. M. Fiorenzano, Samuel N. Quinn, Hannu Parviainen, Ken Rice, Avet Harutyunyan, Akihiko Fukui, Sara Seager, Elisa V. Quintana, Massimo Cecconi, Mark E. Rose, R. Cloutier, Luca Di Fabrizio, Joshua N. Winn, Alessandro Sozzetti, Arjun B. Savel, Andrew Collier Cameron, David Charbonneau, Rachel A. Matson, Michel Mayor, Dimitar Sasselov, Christophe Lovis, Stéphane Udry, Gábor Fűrész, Xavier Dumusque, Cloutier, R [0000-0001-5383-9393], Charbonneau, D [0000-0002-9003-484X], Stassun, KG [0000-0002-3481-9052], Murgas, F [0000-0001-9087-1245], Mortier, A [0000-0001-7254-4363], Massey, R [0000-0001-8879-7138], Lissauer, JJ [0000-0001-6513-1659], Latham, DW [0000-0001-9911-7388], Haywood, RD [0000-0001-9140-3574], Guerra, P [0000-0002-4308-2339], Giacalone, SA [0000-0002-8965-3969], Bieryla, A [0000-0001-6637-5401], Winn, J [0000-0002-4265-047X], Watson, CA [0000-0002-9718-3266], Vanderspek, R [0000-0001-6763-6562], Udry, S [0000-0001-7576-6236], Tamura, M [0000-0002-6510-0681], Sozzetti, A [0000-0002-7504-365X], Shporer, A [0000-0002-1836-3120], Ségransan, D [0000-0003-2355-8034], Seager, S [0000-0002-6892-6948], Savel, AB [0000-0002-2454-768X], Sasselov, D [0000-0001-7014-1771], Rose, M [0000-0003-4724-745X], Ricker, G [0000-0003-2058-6662], Rice, K [0000-0002-6379-9185], Quintana, EV [0000-0003-1309-2904], Quinn, SN [0000-0002-8964-8377], Piotto, G [0000-0002-9937-6387], Phillips, D [0000-0001-5132-1339], Pedani, M [0000-0002-5752-6260], Parviainen, H [0000-0001-5519-1391], Palle, E [0000-0003-0987-1593], Narita, N [0000-0001-8511-2981], Molinari, E [0000-0002-1742-7735], Micela, G [0000-0002-9900-4751], Mayor, M [0000-0002-9352-5935], Matson, RA [0000-0001-7233-7508], López-Morales, M [0000-0003-3204-8183], Kusakabe, N [0000-0001-9194-1268], Jensen, ELN [0000-0002-4625-7333], Jenkins, JM [0000-0002-4715-9460], Huang, CX [0000-0003-0918-7484], Howell, SB [0000-0002-2532-2853], Fukui, A [0000-0002-4909-5763], Esquerdo, GA [0000-0002-9789-5474], Esparza-Borges, E [0000-0002-2341-3233], Dumusque, X [0000-0002-9332-2011], Dressing, CD [0000-0001-8189-0233], Collins, KA [0000-0001-6588-9574], Cameron, AC [0000-0002-8863-7828], Christiansen, JL [0000-0002-8035-4778], Buchhave, LA [0000-0003-1605-5666], Boschin, W [0000-0001-9978-9109], Apollo - University of Cambridge Repository, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), Radial velocity, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Radius, 3rd-DAS, Sitting, Exoplantet strcuture, QC Physics, Space and Planetary Science, Planet, astro-ph.EP, Period (geology), QB Astronomy, Planetary system formation, Low mass stars, Astrophysics::Earth and Planetary Astrophysics, Transit photometry, QC, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics, QB
Abstract: Studies of close-in planets orbiting M dwarfs have suggested that the M dwarf radius valley may be well-explained by distinct formation timescales between enveloped terrestrials, and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally-driven mass loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short period planet TOI-1634 b ($P=0.989$ days, $F=121 F_{\oplus}$, $r_p = 1.790^{+0.080}_{-0.081} R_{\oplus}$) orbiting a nearby M2 dwarf ($K_s=8.7$, $R_s=0.45 R_{\odot}$, $M_s=0.50 M_{\odot}$) and whose size and orbital period sit within the M dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of $4.91^{+0.68}_{-0.70} M_{\oplus}$, which makes TOI-1634 b inconsistent with an Earth-like composition at $5.9\sigma$ and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky portion that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of the Earth favors the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with $M_s\lesssim 0.5 M_{\odot}$., Comment: 27 pages, 13 figures, accepted to AAS journals. Our time series are included as a csv file in the arXiv source files
Published: 2021

36. Hot planets around cool stars - two short-period mini-Neptunes transiting the late K-dwarf TOI-1260

Author: Grzegorz Nowak, Scott McDermott, Eike W. Guenther, Daniele Locci, J. D. Twicken, L. M. Serrano, Keivan G. Stassun, Hannah L. M. Osborne, Martin Paegert, Vincent Van Eylen, M. Fridlund, Enric Palle, P. Guerra, Oscar Barragán, Teriyuki Hirano, George R. Ricker, Rafael Luque, Ilaria Carleo, Alexis M. S. Smith, David W. Latham, Davide Gandolfi, Sascha Grziwa, Elisabeth Matthews, C. E. Brasseur, Roland Vanderspek, Knicole D. Colón, Stephen R. Kane, Steve B. Howell, Seth Redfield, Simon Albrecht, Ian Crossfield, A. M. Levine, E. Goffo, Tianjun Gan, Iskra Georgieva, Samuel N. Quinn, Joshua E. Schlieder, Joshua N. Winn, William D. Cochran, Elise Furlan, Emil Knudstrup, Petr Kabath, Erica J. Gonzales, K. W. F. Lam, Carina M. Persson, Allyson Bieryla, Karen A. Collins, Jon M. Jenkins, Sara Seager, Szilard Csizmadia, Peter Tenenbaum, M. Esposito, N. Scott, Rachel A. Matson, Eric L. N. Jensen, J. Korth, David R. Ciardi, Hans J. Deeg, and John H. Livingston
Subjects: TOI-1260b, Atmospheres, Astrophysics, photometric [techniques], techniques: photometric, Planet, stars: low-mass, techniques: radial velocities, Radial Velocities, TOOL, Planetary Systems, low-mass [stars], individual: TOI-1260b, c [planets and satellites], composition [planets and satellites], Physics, Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: atmospheres, SPECTROSCOPY, planets and satellites: composition, radial velocities [techniques], Planets and Satellites, EXOPLANETS, Photoevaporation, Exoplanet, Radial velocity, Astrophysics::Earth and Planetary Astrophysics, ATMOSPHERES, Composition, Dwarf star, Metallicity, MODELS, FOS: Physical sciences, SUPER-EARTH, Individual, MASS, Photometric, AGE, planets and satellites: individual: TOI-1260b, Low-Mass, planetary systems, RADIAL-VELOCITY, Astronomy and Astrophysics, atmospheres [planets and satellites], Planetary system, Stars, Techniques, M-CIRCLE-PLUS, Photometry (astronomy), Space and Planetary Science, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the discovery and characterization of two sub-Neptunes in close orbits, as well as a tentative outer planet of a similar size, orbiting TOI-1260 – a low metallicity K6 V dwarf star. Photometry from Transiting Exoplanet Survey Satellite(TESS) yields radii of Rb = 2.33 ± 0.10 and Rc = 2.82 ± 0.15 R⊕, and periods of 3.13 and 7.49 d for TOI-1260 b and TOI-1260 c, respectively. We combined the TESS data with a series of ground-based follow-up observations to characterize the planetary system. From HARPS-N high-precision radial velocities we obtain Mb = $8.6 _{ - 1.5 } ^ { + 1.4 }$ and Mc = $11.8 _{ - 3.2 } ^ { + 3.4 }$ M⊕. The star is moderately active with a complex activity pattern, which necessitated the use of Gaussian process regression for both the light-curve detrending and the radial velocity modelling, in the latter case guided by suitable activity indicators. We successfully disentangle the stellar-induced signal from the planetary signals, underlining the importance and usefulness of the Gaussian process approach. We test the system’s stability against atmospheric photoevaporation and find that the TOI-1260 planets are classic examples of the structure and composition ambiguity typical for the 2–3 R⊕ range.
Published: 2021

37. Two Young Planetary Systems around Field Stars with Ages between 20 and 320 Myr from TESS

Author: Jonathan Irwin, Rachel A. Matson, Elise Furlan, Eric L. N. Jensen, Lamisha Khan, Nicholas J. Scott, Thiam-Guan Tan, George Zhou, John F. Kielkopf, Andrew Vanderburg, Joseph E. Rodriguez, Guillermo Torres, Knicole D. Colón, Lars A. Buchhave, Anaka Landrigan, B. Wohler, Pamela Rowden, Allyson Bieryla, Steve B. Howell, David R. Anderson, Karen A. Collins, Jon M. Jenkins, Perry Berlind, Brad D. Carter, Richard G. West, George R. Ricker, Michael L. Calkins, David Charbonneau, K. I. Collins, D. A. Yahalomi, Gilbert A. Esquerdo, Sara Seager, David W. Latham, Andrew W. Mann, Rhodes Hart, Joshua N. Winn, Nicholas M. Law, Roland Vanderspek, Russel White, Tansu Daylan, Carl Ziegler, Ismael Mireles, Luke G. Bouma, Stephanie T. Douglas, Samuel N. Quinn, Chelsea X. Huang, Coel Hellier, C. E. Brasseur, and Chris Stockdale
Subjects: 010504 meteorology & atmospheric sciences, Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Gyrochronology, education, 010303 astronomy & astrophysics, QB600, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, Astronomy and Astrophysics, Radius, Planetary system, Exoplanet, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Equivalent width, Astrophysics - Earth and Planetary Astrophysics
Abstract: Planets around young stars trace the early evolution of planetary systems. We report the discovery and validation of two planetary systems with ages $\lesssim 300$ Myr from observations by the Transiting Exoplanet Survey Satellite. TOI-251 is a 40-320 Myr old G star hosting a 2.74 +0.18/-0.18 REarth mini-Neptune with a 4.94 day period. TOI-942 is a 20-160 Myr old K star hosting a system of inflated Neptune-sized planets, with TOI-942b orbiting with a period of 4.32 days, with a radius of 4.81 +0.20/-0.20 REarth, and TOI-942c orbiting in a period of 10.16 days with a radius of 5.79 +0.19/-0.18 REarth. Though we cannot place either host star into a known stellar association or cluster, we can estimate their ages via their photometric and spectroscopic properties. Both stars exhibit significant photometric variability due to spot modulation, with measured rotation periods of $\sim 3.5$ days. These stars also exhibit significant chromospheric activity, with age estimates from the chromospheric calcium emission lines and X-ray fluxes matching that estimated from gyrochronology. Both stars also exhibit significant lithium absorption, similar in equivalent width to well-characterized young cluster members. TESS has the potential to deliver a population of young planet-bearing field stars, contributing significantly to tracing the properties of planets as a function of their age., Accepted for publication in AJ
Published: 2021

38. The NASA High-Resolution Speckle Interferometric Imaging Program: Validation and Characterization of Exoplanets and Their Stellar Hosts

Author: Nicholas J. Scott, Elise Furlan, David R. Ciardi, Steve B. Howell, Crystal L. Gnilka, Rachel A. Matson, Kathryn V. Lester, and Mark E. Everett
Subjects: Astronomy, Geophysics. Cosmic physics, FOS: Physical sciences, QB1-991, 010501 environmental sciences, 01 natural sciences, Kepler, speckle interferometry, binary stars, Speckle pattern, Planet, 0103 physical sciences, Binary star, Transit (astronomy), 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), QC801-809, high-resolution imaging, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Exoplanet, exoplanets, Astrophysics - Solar and Stellar Astrophysics, Extraterrestrial life, exoplanet demographics, Speckle imaging, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: Starting in 2008, NASA has provided the exoplanet community an observational program aimed at obtaining the highest resolution imaging available as part of its mission to validate and characterize exoplanets, as well as their stellar environments, in search of life in the Universe. Our current program uses speckle interferometry in the optical (320–1,000 nm) with new instruments on the 3.5-m WIYN and both 8-m Gemini telescopes. Starting with Kepler and K2 follow-up, we now support TESS and other space- and ground-based exoplanet related discovery and characterization projects. The importance of high-resolution imaging for exoplanet research comes via identification of nearby stellar companions that can dilute the transit signal and confound derived exoplanet and stellar parameters. Our observations therefore provide crucial information allowing accurate planet and stellar properties to be determined. Our community program obtains high-resolution imagery, reduces the data, and provides all final data products, without any exclusive use period, to the community via the Exoplanet Follow-Up Observation Program (ExoFOP) website maintained by the NASA Exoplanet Science Institute. This paper describes the need for high-resolution imaging and gives details of the speckle imaging program, highlighting some of the major scientific discoveries made along the way.
Published: 2021
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39. Discovery of a hot, transiting, Earth-sized planet and a second temperate, non-transiting planet around the M4 dwarf GJ 3473 (TOI-488)

Author: David R. Ciardi, Xavier Bonfils, Richard P. Schwarz, M. Lafarga, K. Kawauchi, P. Guerra, Sabine Reffert, E. Esparza-Borges, David W. Latham, Nuno C. Santos, H. Harakawa, Enric Palle, Stefan Dreizler, Víctor J. S. Béjar, Mayuko Mori, Noriharu Watanabe, S. Stock, Ansgar Reiners, Bernie Shiao, Joshua E. Schlieder, Sandra V. Jeffers, Diana Kossakowski, François Bouchy, A. Fukui, Motohide Tamura, A. Ueda, Masayuki Kuzuhara, Takayuki Kotani, Rachel A. Matson, Adrian Kaminski, D. D. Della-Rose, Steve B. Howell, Joshua N. Winn, Sara Seager, J. P. de Leon, Jose A. Caballero, Masahiro Ikoma, Roland Vanderspek, J. Kemmer, Norio Narita, Erica J. Gonzales, Ian Crossfield, N. Crouzet, John H. Livingston, Yuka Terada, Tianjun Gan, Philip S. Muirhead, T. Forveille, R. Cloutier, P. Schöfer, K. I. Collins, J. D. Twicken, Andreas Quirrenbach, Elisabeth Matthews, Néstor Espinoza, Martin Kürster, Mathias Zechmeister, Carlos Cifuentes, Karan Molaverdikhani, Rafael Luque, M. Omiya, Pedro J. Amado, X. Delfosse, P. T. Boyd, Jon M. Jenkins, Ana Glidden, P. Klagyivik, Taku Nishiumi, Teriyuki Hirano, Juan Carlos Morales, Martin Schlecker, P. Figueira, Jun Nishikawa, S. Vievard, Jose-Manuel Almenara, D. Galadí-Enríquez, Hannu Parviainen, George R. Ricker, Jessie L. Christiansen, T. Kurokawa, A. P. Hatzes, Klaus W. Hodapp, Karen A. Collins, Nicola Astudillo-Defru, P. Bluhm, Yasunori Hori, T. Kimura, Felipe Murgas, Ignasi Ribas, K. Isogai, Th. Henning, M. Cortés-Contreras, E. Herrero, N. Kusakabe, C. Rodríguez López, Z. Essack, German Research Foundation, Max Planck Society, European Commission, Consejo Superior de Investigaciones Científicas (España), Thuringian Ministry of Education, Science and Culture, Klaus Tschira Foundation, Ministerio de Economía y Competitividad (España), Junta de Andalucía, European Research Council, Ministerio de Ciencia, Innovación y Universidades (España), Comisión Nacional de Investigación Científica y Tecnológica (Chile), Science and Technology Facilities Council (UK), Generalitat de Catalunya, Japan Society for the Promotion of Science, Japan Science and Technology Agency, Fundação para a Ciência e a Tecnologia (Portugal), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Institut de Microélectronique, Electromagnétisme et Photonique - Laboratoire d'Hyperfréquences et Caractérisation (IMEP-LAHC), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Instituto Nacional de Técnica Aeroespacial (INTA), Departamento de Matemática y Fı́sica Aplicadas [Concepcion] (DMFA), Universidad Católica de la Santísima Concepción (UCSC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)
Subjects: Extrasolare Planeten und Atmosphären, planets and satellites: detection, FOS: Physical sciences, individual: G 50-16 [Stars], Astrophysics, 01 natural sciences, techniques: photometric, Planet, 0103 physical sciences, techniques: radial velocities, 14. Life underwater, 010306 general physics, 010303 astronomy & astrophysics, planetary systems, Physics, Earth and Planetary Astrophysics (astro-ph.EP), stars: individual: G 50-16, radial velocities [Techniques], photometric [Techniques], stars: late-type, Astronomy and Astrophysics, Planetary systems, detection [Planets and satellites], 13. Climate action, Space and Planetary Science, late-type [Stars], Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Humanities, Astrophysics - Earth and Planetary Astrophysics
Abstract: Full list of authors: Kemmer, J.; Stock, S.; Kossakowski, D.; Kaminski, A.; Molaverdikhani, K.; Schlecker, M.; Caballero, J. A.; Amado, P. J.; Astudillo-Defru, N.; Bonfils, X.; Ciardi, D.; Collins, K. A.; Espinoza, N.; Fukui, A.; Hirano, T.; Jenkins, J. M.; Latham, D. W.; Matthews, E. C.; Narita, N.; Pallé, E.; Parviainen, H.; Quirrenbach, A.; Reiners, A.; Ribas, I.; Ricker, G.; Schlieder, J. E.; Seager, S.; Vanderspek, R.; Winn, J. N.; Almenara, J. M.; Béjar, V. J. S.; Bluhm, P.; Bouchy, F.; Boyd, P.; Christiansen, J. L.; Cifuentes, C.; Cloutier, R.; Collins, K. I.; Cortés-Contreras, M.; Crossfield, I. J. M.; Crouzet, N.; de Leon, J. P.; Della-Rose, D. D.; Delfosse, X.; Dreizler, S.; Esparza-Borges, E.; Essack, Z.; Forveille, Th.; Figueira, P.; Galadí-Enríquez, D.; Gan, T.; Glidden, A.; Gonzales, E. J.; Guerra, P.; Harakawa, H.; Hatzes, A. P.; Henning, Th.; Herrero, E.; Hodapp, K.; Hori, Y.; Howell, S. B.; Ikoma, M.; Isogai, K.; Jeffers, S. V.; Kürster, M.; Kawauchi, K.; Kimura, T.; Klagyivik, P.; Kotani, T.; Kurokawa, T.; Kusakabe, N.; Kuzuhara, M.; Lafarga, M.; Livingston, J. H.; Luque, R.; Matson, R.; Morales, J. C.; Mori, M.; Muirhead, P. S.; Murgas, F.; Nishikawa, J.; Nishiumi, T.; Omiya, M.; Reffert, S.; Rodríguez López, C.; Santos, N. C.; Schöfer, P.; Schwarz, R. P.; Shiao, B.; Tamura, M.; Terada, Y.; Twicken, J. D.; Ueda, A.; Vievard, S.; Watanabe, N.; Zechmeister, M., We present the confirmation and characterisation of GJ 3473 b (G 50-16, TOI-488.01), a hot Earth-sized planet orbiting an M4 dwarf star, whose transiting signal (P = 1.1980035 ± 0.0000018 d) was first detected by the Transiting Exoplanet Survey Satellite (TESS). Through a joint modelling of follow-up radial velocity observations with CARMENES, IRD, and HARPS together with extensive ground-based photometric follow-up observations with LCOGT, MuSCAT, and MuSCAT2, we determined a precise planetary mass, Mb = 1.86 ± 0.30 M·, and radius, Rb = 1.264 ± 0.050 R·. Additionally, we report the discovery of a second, temperate, non-transiting planet in the system, GJ 3473 c, which has a minimum mass, Mc sin i = 7.41 ± 0.91 M·, and orbital period, Pc = 15.509 ± 0.033 d. The inner planet of the system, GJ 3473 b, is one of the hottest transiting Earth-sized planets known thus far, accompanied by a dynamical mass measurement, which makes it a particularly attractive target for thermal emission spectroscopy. © 2020 ESO., CARMENES is an instrument at the Centro Astronomico Hispano-Aleman de Calar Alto (CAHA, Almeria, Spain). CARMENES was funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Cientificas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Planck-Institut fur Astronomie, Instituto de Astrofisica de Andalucia, Landessternwarte Konigstuhl, Institut de Ciencies de l'Espai, Insitut fur Astrophysik Gottingen, Universidad Complutense de Madrid, Thuringer Landessternwarte Tautenburg, Instituto de Astrofisica de Canarias, Hamburger Sternwarte, Centro de Astrobiologia and Centro Astronomico Hispano-Aleman), with additional contributions by the Spanish Ministry of Economy, the German Science Foundation through the Major Research Instrumentation Programme and Deutsche Forschungsgemeinschaft (DFG) Research Unit FOR2544 "Blue Planets around Red Stars", the Klaus Tschira Stiftung, the states of Baden-Wurttemberg and Niedersachsen, and by the Junta de Andalucia. Part of this work was funded by the Ministerio de Ciencia e Innovacion via projects PID2019-109522GB-C51/2/3/4 and AYA2016-79425C3-1/2/3-P, (MEXT/)JSPS KAKENHI via grants 15H02063, JP17H04574, 18H05442, JP18H01265, JP18H05439, 19J11805, JP19K14783, and 22000005, JST PRESTO via grant JPMJPR1775, FCT/MCTES through national funds (PIDDAC, PTDC/FIS-AST/32113/2017) via grant UID/FIS/04434/2019, FEDER - Fundo Europeu de Desenvolvimento Regional through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI-010145-FEDER-032113), the FONDECYT project 3180063, Fundacao para a Ciencia e a Tecnologia through national funds and by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao by these grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020; PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113; PTDC/FISAST/28953/2017 & POCI-01-0145-FEDER-028953. and the International Graduate Program for Excellence in Earth-Space Science. Part of the data analysis was carried out on the Multi-wavelength Data Analysis System operated by the Astronomy Data Center, National Astronomical Observatory of Japan. Funding for the TESS mission is provided by NASA's Science Mission directorate. We acknowledge the use of public TESS Alert data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Resources supporting this work were provided by the NASA High-End Computing Program through the NASA Advanced Supercomputing Division at Ames Research Center for the production of the SPOC data products. This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes. This work makes use of observations from the LCOGT network. The analysis of this work has made use of a wide variety of public available software packages that are not referenced in the manuscript: Exo-Striker (Trifonov 2019), astropy (Astropy Collaboration 2018), scipy (Virtanen et al. 2020), numpy (Oliphant 2006), matplotlib (Hunter 2007), tqdm (da Costa-Luis 2019), pandas (The pandas development team 2020), seaborn (Waskom et al. 2020), lightkurve (Lightkurve Collaboration 2018) and PyFITS (Barrett et al. 2012).
Published: 2020

40. The First Habitable-zone Earth-sized Planet from TESS. I. Validation of the TOI-700 System

Author: Roland Vanderspek, Michele L. Silverstein, Danielle Dineen, Ethan Kruse, Stephen A. Rinehart, Matthew S. Clement, Emily A. Gilbert, Jessie L. Christiansen, Courtney D. Dressing, Joseph E. Rodriguez, Tansu Daylan, Christopher Lam, Keivan G. Stassun, Tianjun Gan, Sebastian Zieba, Nikole K. Lewis, Mario Di Sora, Veselin B. Kostov, Jonathan Brande, Jennifer G. Winters, George R. Ricker, Eric T. Wolf, Teresa Monsue, Eric D. Lopez, Karen A. Collins, Laura Kreidberg, Wei-Chun Jao, Stephen R. Kane, Naylynn Tañón Reyes, Andrew Couperus, Carl Ziegler, F. Mallia, Benjamin J. Shappee, Gabrielle Suissa, Kelsey Hoffman, Giovanni Covone, Laura D. Vega, Jeffrey C. Smith, Allison Youngblood, Bárbara Rojas-Ayala, Knicole D. Colón, Patricia T. Boyd, Fred C. Adams, Sean N. Raymond, Joel D. Hartman, Todd J. Henry, Geronimo L. Villanueva, Ravi Kumar Kopparapu, Avi Mandell, Christopher J. Burke, Giada Arney, Brianna Galgano, Mark E. Everett, Peter Tenenbaum, Gáspár Á. Bakos, Cesar Briceno, Samuel N. Quinn, Elisa V. Quintana, Mackenna L. Wood, Eve J. Lee, Alex R. Howe, Sarah E. Logsdon, Thomas Fauchez, Zahra Essack, Dennis M. Conti, Andrew W. Mann, Nora L. Eisner, Rishi R. Paudel, Jack J. Lissauer, Quadry Chance, Peter Plavchan, Lucianne M. Walkowicz, Fergal Mullally, Vladimir Airapetian, Eliot Halley Vrijmoet, Eric L. N. Jensen, David W. Latham, Thomas Barclay, Benjamin J. Hord, Joshua E. Schlieder, Nicholas M. Law, Jon M. Jenkins, Joshua N. Winn, Steve B. Howell, Susan E. Mullally, Andrew Vanderburg, David R. Ciardi, Lisa Kaltenegger, Jason F. Rowe, Luca Cacciapuoti, Giovanni Isopi, Sara Seager, Rachel A. Matson, Ryan Cloutier, Daria Pidhorodetska, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Gilbert, E. A., Barclay, T., Schlieder, J. E., Quintana, E. V., Hord, B. J., Kostov, V. B., Lopez, E. D., Rowe, J. F., Hoffman, K., Walkowicz, L. M., Silverstein, M. L., Rodriguez, J. E., Vanderburg, A., Suissa, G., Airapetian, V. S., Clement, M. S., Raymond, S. N., Mann, A. W., Kruse, E., Lissauer, J. J., Colon, K. D., Kopparapu, R. K., Kreidberg, L., Zieba, S., Collins, K. A., Quinn, S. N., Howell, S. B., Ziegler, C., Vrijmoet, E. H., Adams, F. C., Arney, G. N., Boyd, P. T., Brande, J., Burke, C. J., Cacciapuoti, L., Chance, Q., Christiansen, J. L., Covone, G., Daylan, T., Dineen, D., Dressing, C. D., Essack, Z., Fauchez, T. J., Galgano, B., Howe, A. R., Kaltenegger, L., Kane, S. R., Lam, C., Lee, E. J., Lewis, N. K., Logsdon, S. E., Mandell, A. M., Monsue, T., Mullally, F., Mullally, S. E., Paudel, R. R., Pidhorodetska, D., Plavchan, P., Reyes, N. T., Rinehart, S. A., Rojas-Ayala, B., Smith, J. C., Stassun, K. G., Tenenbaum, P., Vega, L. D., Villanueva, G. L., Wolf, E. T., Youngblood, A., Ricker, G. R., Vanderspek, R. K., Latham, D. W., Seager, S., Winn, J. N., Jenkins, J. M., Bakos, G. A., Briceño, C., Ciardi, D. R., Cloutier, R., Conti, D. M., Couperus, A., Di Sora, M., Eisner, N. L., Everett, M. E., Gan, T., Hartman, J. D., Henry, T., Isopi, G., Jao, W. -C., Jensen, E. L. N., Law, N., Mallia, F., Matson, R. A., Shappee, B. J., Le Wood, M., and Winters, J. G.
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Dwarf star, 010504 meteorology & atmospheric sciences, Atmospheric escape, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], James Webb Space Telescope, Ecliptic, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, 01 natural sciences, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, 0103 physical sciences, Transit (astronomy), 010303 astronomy & astrophysics, Circumstellar habitable zone, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract: We present the discovery and validation of a three-planet system orbiting the nearby (31.1 pc) M2 dwarf star TOI-700 (TIC 150428135). TOI-700 lies in the TESS continuous viewing zone in the Southern Ecliptic Hemisphere; observations spanning 11 sectors reveal three planets with radii ranging from 1 R$_\oplus$ to 2.6 R$_\oplus$ and orbital periods ranging from 9.98 to 37.43 days. Ground-based follow-up combined with diagnostic vetting and validation tests enable us to rule out common astrophysical false-positive scenarios and validate the system of planets. The outermost planet, TOI-700 d, has a radius of $1.19\pm0.11$ R$_\oplus$ and resides in the conservative habitable zone of its host star, where it receives a flux from its star that is approximately 86% of the Earth's insolation. In contrast to some other low-mass stars that host Earth-sized planets in their habitable zones, TOI-700 exhibits low levels of stellar activity, presenting a valuable opportunity to study potentially-rocky planets over a wide range of conditions affecting atmospheric escape. While atmospheric characterization of TOI-700 d with the James Webb Space Telescope (JWST) will be challenging, the larger sub-Neptune, TOI-700 c (R = 2.63 R$_\oplus$), will be an excellent target for JWST and beyond. TESS is scheduled to return to the Southern Hemisphere and observe TOI-700 for an additional 11 sectors in its extended mission, which should provide further constraints on the known planet parameters and searches for additional planets and transit timing variations in the system., Accepted for publication in AJ (30 pages, 13 figures, 4 tables, 2 appendices)
Published: 2020

41. A pair of TESS planets spanning the radius valley around the nearby mid-M dwarf LTT 3780

Author: Andrew W. Mann, Dimitar Sasselov, Jon M. Jenkins, Charles A. Beichman, Steve B. Howell, F. Lienhard, David Charbonneau, Joseph E. Rodriguez, Giampaolo Piotto, Ken Rice, Avet Harutyunyan, Matteo Pinamonti, Eric D. Lopez, Laura Kreidberg, David W. Latham, Xavier Dumusque, Mercedes Lopez-Morales, Michel Mayor, George R. Ricker, Nicola Astudillo-Defru, Jack J. Lissauer, Douglas A. Caldwell, Kevin I. Collins, A. Magazzu, Joseph D. Twicken, Joshua E. Schlieder, Andrew Collier Cameron, David F. Phillips, Xavier Delfosse, Joshua N. Winn, Dennis M. Conti, M. Stalport, Rosario Cosentino, Sara Seager, Rodrigo F. Díaz, Annelies Mortier, Sébastien Lépine, Patricia T. Boyd, Rachel A. Matson, John F. Kielkopf, David R. Ciardi, Stéphane Udry, Cesar Briceno, Thierry Forveille, Nicholas M. Law, Samuel N. Quinn, Adriano Ghedina, Lars A. Buchhave, Ennio Poretti, Nuno C. Santos, Karen A. Collins, René Doyon, Xavier Bonfils, Emilio Molinari, Aldo F. M. Fiorenzano, Jason D. Eastman, Eric L. N. Jensen, Étienne Artigau, Alessandro Sozzetti, Jonathan Irwin, Michael Vezie, Benjamin V. Rackham, Pedro Figueira, Mario Damasso, L. Mignon, Damien Ségransan, Francesco Pepe, Claudio Melo, Carl Ziegler, Jennifer G. Winters, Elisabeth Matthews, José Renan de Medeiros, Luca Di Fabrizio, Giuseppina Micela, Christophe Lovis, Ian J. M. Crossfield, François Bouchy, Christopher J. Burke, J. M. Almenara, Roland Vanderspek, John Asher Johnson, Ryan Cloutier, Peter Tenenbaum, Christopher A. Watson, Courtney D. Dressing, Robert Massey, Erica J. Gonzales, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Universidad Católica de la Santísima Concepción (UCSC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Cloutier, R [0000-0001-5383-9393], Eastman, JD [0000-0003-3773-5142], Rodriguez, JE [0000-0001-8812-0565], Mortier, A [0000-0001-7254-4363], Pinamonti, M [0000-0002-4445-1845], Lienhard, F [0000-0003-4047-0771], Latham, DW [0000-0001-9911-7388], Collins, KA [0000-0001-6588-9574], Massey, R [0000-0001-8879-7138], Winters, JG [0000-0001-6031-9513], Charbonneau, D [0000-0002-9003-484X], Ziegler, C [0000-0002-0619-7639], Matthews, E [0000-0003-0593-1560], Kreidberg, L [0000-0003-0514-1147], Quinn, SN [0000-0002-8964-8377], Ricker, G [0000-0003-2058-6662], Vanderspek, R [0000-0001-6763-6562], Seager, S [0000-0002-6892-6948], Winn, J [0000-0002-4265-047X], Jenkins, JM [0000-0002-4715-9460], Udry, S [0000-0001-7576-6236], Twicken, JD [0000-0002-6778-7552], Tenenbaum, P [0000-0002-1949-4720], Sozzetti, A [0000-0002-7504-365X], Ségransan, D [0000-0003-2355-8034], Schlieder, JE [0000-0001-5347-7062], Sasselov, D [0000-0001-7014-1771], Santos, NC [0000-0003-4422-2919], Rackham, BV [0000-0002-3627-1676], Poretti, E [0000-0003-1200-0473], Piotto, G [0000-0002-9937-6387], Molinari, E [0000-0002-1742-7735], Micela, G [0000-0002-9900-4751], De Medeiros, JR [0000-0001-8218-1586], Matson, RA [0000-0001-7233-7508], Mann, AW [0000-0003-3654-1602], Magazzú, A [0000-0003-1259-4371], López-Morales, M [0000-0003-3204-8183], Lissauer, JJ [0000-0001-6513-1659], Law, N [0000-0001-9380-6457], Kielkopf, JF [0000-0003-0497-2651], Jensen, ELN [0000-0002-4625-7333], Howell, SB [0000-0002-2532-2853], Ghedina, A [0000-0003-4702-5152], Forveille, T [0000-0003-0536-4607], Figueira, P [0000-0001-8504-283X], Dumusque, X [0000-0002-9332-2011], Dressing, CD [0000-0001-8189-0233], Díaz, RF [0000-0001-9289-5160], Conti, DM [0000-0003-2239-0567], Collins, KI [0000-0003-2781-3207], Ciardi, D [0000-0002-5741-3047], Caldwell, DA [0000-0003-1963-9616], Burke, C [0000-0002-7754-9486], Buchhave, L [0000-0003-1605-5666], Boyd, P [0000-0003-0442-4284], and Apollo - University of Cambridge Repository
Subjects: Radial velocity, 010504 meteorology & atmospheric sciences, Stellar mass, NDAS, FOS: Physical sciences, Astrophysics, M dwarf stars, 01 natural sciences, Planet, 0103 physical sciences, QB Astronomy, Spectroscopy, 010303 astronomy & astrophysics, Exoplanet systems, QC, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy and Astrophysics, Radius, Planetary system, Photoevaporation, Stars, QC Physics, Space and Planetary Science, astro-ph.EP, Transit photometry, Low Mass, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the confirmation of two new planets transiting the nearby mid-M dwarf LTT 3780 (TIC 36724087, TOI-732, $V=13.07$, $K_s=8.204$, $R_s$=0.374 R$_{\odot}$, $M_s$=0.401 M$_{\odot}$, d=22 pc). The two planet candidates are identified in a single TESS sector and are validated with reconnaissance spectroscopy, ground-based photometric follow-up, and high-resolution imaging. With measured orbital periods of $P_b=0.77$ days, $P_c=12.25$ days and sizes $r_{p,b}=1.33\pm 0.07$ R$_{\oplus}$, $r_{p,c}=2.30\pm 0.16$ R$_{\oplus}$, the two planets span the radius valley in period-radius space around low mass stars thus making the system a laboratory to test competing theories of the emergence of the radius valley in that stellar mass regime. By combining 63 precise radial-velocity measurements from HARPS and HARPS-N, we measure planet masses of $m_{p,b}=2.62^{+0.48}_{-0.46}$ M$_{\oplus}$ and $m_{p,c}=8.6^{+1.6}_{-1.3}$ M$_{\oplus}$, which indicates that LTT 3780b has a bulk composition consistent with being Earth-like, while LTT 3780c likely hosts an extended H/He envelope. We show that the recovered planetary masses are consistent with predictions from both photoevaporation and from core-powered mass loss models. The brightness and small size of LTT 3780, along with the measured planetary parameters, render LTT 3780b and c as accessible targets for atmospheric characterization of planets within the same planetary system and spanning the radius valley., Comment: Accepted to AJ. 8 figures, 6 tables. CSV file of the RV measurements (i.e. Table 2) are included in the source code
Published: 2020

42. Visual Orbits of Spectroscopic Binaries with the CHARA Array. III. HD 8374 and HD 24546

Author: Chris Farrington, Matthew W. Muterspaugh, John D. Monnier, T. ten Brummelaar, Francis C. Fekel, Judit Sturmann, Samuel A. Weiss, Douglas R. Gies, Rachel A. Matson, Zhao Guo, Gail H. Schaefer, and Kathryn V. Lester
Subjects: Physics, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Effective temperature, 01 natural sciences, 3. Good health, CHARA array, Radial velocity, Stars, Palomar Testbed Interferometer, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Binary star, Spectral energy distribution, 010303 astronomy & astrophysics, Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences
Abstract: We present the visual orbits of two long period spectroscopic binary stars, HD 8374 and HD 24546, using interferometric observations acquired with the CHARA Array and the Palomar Testbed Interferometer. We also obtained new radial velocities from echelle spectra using the APO 3.5 m and Fairborn 2.0 m telescopes. By combining the visual and spectroscopic observations, we solve for the full, three-dimensional orbits and determine the stellar masses and distances to within 3% uncertainty. We then estimate the effective temperature and radius of each component star through Doppler tomography and spectral energy distribution analyses, in order to compare the observed stellar parameters to the predictions of stellar evolution models. For HD 8374, we find masses of M1 = 1.636 +/- 0.050 Msun and M2 = 1.587 +/- 0.049 Msun, radii of R1 = 1.84 +/- 0.05 Rsun and R2 = 1.66 +/- 0.12 Rsun, temperatures of Teff1 = 7280 +/- 110 K and Teff2 = 7280 +/- 120 K, and an estimated age of 1.0 Gyr. For HD 24546, we find masses of M1 = 1.434 +/- 0.014 Msun and M2 = 1.409 +/- 0.014 Msun, radii of R1 = 1.67 +/- 0.06 Rsun and R2 = 1.60 +/- 0.10 Rsun, temperatures of Teff1 = 6790 +/- 120 K and Teff2 = 6770 +/- 90 K, and an estimated age of 1.4 Gyr. HD 24546 is therefore too old to be a member of the Hyades cluster, despite its physical proximity to the group., 18 pages, 10 figures. Accepted for publication in AJ
Published: 2020

43. WASP-4 Is Accelerating toward the Earth

Author: Luke G. Bouma, Heather A. Knutson, Steve B. Howell, Rachel A. Matson, Howard Isaacson, Joshua N. Winn, and Andrew W. Howard
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Line-of-sight, 010504 meteorology & atmospheric sciences, Apsidal precession, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Orbital decay, Orbital period, 01 natural sciences, Radial velocity, Acceleration, Space and Planetary Science, 0103 physical sciences, Hot Jupiter, Magnitude (astronomy), Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract: The orbital period of the hot Jupiter WASP-4b appears to be decreasing at a rate of $-8.64 \pm 1.26$ msec/yr, based on transit-timing measurements spanning 12 years. Proposed explanations for the period change include tidal orbital decay, apsidal precession, and acceleration of the system along the line of sight. To investigate further, we performed new radial velocity measurements and speckle imaging of WASP-4. The radial-velocity data show that the system is accelerating towards the Sun at a rate of $-0.0422\pm 0.0028$ m/s/day. The associated Doppler effect should cause the apparent period to shrink at a rate of $-5.94 \pm 0.39$ msec/yr, comparable to the observed rate. Thus, the observed change in the transit period is mostly or entirely produced by the line-of-sight acceleration of the system. This acceleration is probably caused by a wide-orbiting companion of mass 10-300$\,M_{\rm Jup}$ and orbital distance 10-100$\,$AU, based on the magnitude of the radial-velocity trend and the non-detection of any companion in the speckle images. We expect that the orbital periods of 1 out of 3 hot Jupiters will change at rates similar to WASP-4b, based on the hot-Jupiter companion statistics of Knutson et al. (2014). Continued radial velocity monitoring of hot Jupiters is therefore essential to distinguish the effects of tidal orbital decay or apsidal precession from line-of-sight acceleration., Comment: ApJL accepted
Published: 2020

44. TESS Spots a Hot Jupiter with an Inner Transiting Neptune

Author: Stephen R. Kane, Erica J. Gonzales, Savita Mathur, Hodari Sadiki James, Sara Seager, David W. Latham, Leonardo A. Paredes, Todd J. Henry, Keivan G. Stassun, Emmanuel Jehin, Iskra Georgieva, Joseph E. Rodriguez, Vincent Van Eylen, Eric L. N. Jensen, Elisabeth Matthews, Rachel A. Matson, Avi Shporer, Khalid Barkaoui, Lizhou Sha, Wei-Chun Jao, Malcolm Fridlund, George R. Ricker, Michaël Gillon, Ian Wong, Carina M. Persson, Roland Vanderspek, Maximilian N. Günther, Karen A. Collins, Chelsea X. Huang, Andrew Vanderburg, Thiam-Guan Tan, George Zhou, Guillermo Torres, Francisco J. Pozuelos, Jack J. Lissauer, Juliette C. Becker, Robert F. Goeke, Mark E. Rose, Ian J. M. Crossfield, Joshua E. Schlieder, Stephen A. Rinehart, Jon M. Jenkins, Joshua N. Winn, Steve B. Howell, Christopher J. Burke, Andrew W. Mann, Eric B. Ting, Samuel N. Quinn, Enric Palle, Davide Gandolfi, and Kevin I. Collins
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), Brightness, 010504 meteorology & atmospheric sciences, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, 01 natural sciences, Exoplanet, Photometry (optics), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Neptune, Planet, 0103 physical sciences, Hot Jupiter, Adaptive optics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract: Hot Jupiters are rarely accompanied by other planets within a factor of a few in orbital distance. Previously, only two such systems have been found. Here, we report the discovery of a third system using data from the Transiting Exoplanet Survey Satellite (TESS). The host star, TOI-1130, is an 11th magnitude K-dwarf in the Gaia G band. It has two transiting planets: a Neptune-sized planet ($3.65\pm 0.10$ $R_E$) with a 4.1-day period, and a hot Jupiter ($1.50^{+0.27}_{-0.22}$ $R_J$) with an 8.4-day period. Precise radial-velocity observations show that the mass of the hot Jupiter is $0.974^{+0.043}_{-0.044}$ $M_J$. For the inner Neptune, the data provide only an upper limit on the mass of 0.17 $M_J$ (3$\sigma$). Nevertheless, we are confident the inner planet is real, based on follow-up ground-based photometry and adaptive optics imaging that rule out other plausible sources of the TESS transit signal. The unusual planetary architecture of and the brightness of the host star make TOI-1130 a good test case for planet formation theories, and an attractive target for future spectroscopic observations., Comment: accepted by ApJL
Published: 2020

45. TOI-257b (HD 19916b): A Warm sub-Saturn Orbiting an Evolved F-type Star

Author: Andrés Jordán, Derek Buzasi, K. I. Collins, Joshua Pepper, Jon M. Jenkins, Alexander Lyttle, Martin Schlecker, Ismael Mireles, Sara Seager, Brett C. Addison, Andrea Miglio, Jack Okumura, Savita Mathur, Christopher Tylor, Daniel R. Hey, Victor Silva Aguirre, Zhao Guo, Tansu Daylan, Paula Sarkis, Mikkel N. Lund, J. S. Bentley, Martin Bo Nielsen, Joshua E. Schlieder, Keivan G. Stassun, Aldo Serenelli, Jonathan Horner, Stephen R. Kane, Tiago L. Campante, B. D. Carter, Joshua N. Winn, Hui Zhang, Diana Kossakowski, Thomas Henning, Brendan P. Bowler, Rasmus Handberg, Jake T. Clark, Warrick H. Ball, Matthew W. Mengel, Pamela Rowden, L. González-Cuesta, Karen A. Collins, Andrew W. Mann, Nicholas M. Law, John F. Kielkopf, B. Mosser, Daniel Huber, Ian J. M. Crossfield, Mathieu Clerte, Michaela Collins, Ashley Chontos, Songhu Wang, Belinda A. Nicholson, Pascal Torres, Thomas Kallinger, Robert A. Wittenmyer, Stephen C. Marsden, Andrew Vanderburg, Dag Evensberget, N. Themeßl, Rachel A. Matson, José Dias do Nascimento, David W. Latham, Cenk Kayhan, Timothy R. Bedding, Allen B. Davis, Emilie Laychock, J. O'Connor, Néstor Espinoza, B. Cale, Andrius Burnelis, S. Hekker, Steven D. Kawaler, Avi Shporer, Duncan J. Wright, Sarbani Basu, Peter Plavchan, James S. Kuszlewicz, Guy R. Davies, Teo Mocnik, Leandro de Almeida, Jason D. Eastman, Carl Ziegler, Rafael Brahm, Enrico Corsaro, William J. Chaplin, C. G. Tinney, Catherine Stevens, Rafael A. García, Sergi Blanco-Cuaresma, Steve B. Howell, Alexis Heitzmann, Roland Vanderspek, Thiam-Guan Tan, George R. Ricker, Addison, Brett C, Wright, Duncan J, Nicholson, Belinda A, Cale, Bryson, Mocnik, Teo, Huber, Daniel, Plavchan, Peter, Wittenmyer, Robert A, Vanderburg, Andrew, Chaplin, William J, Chontos, Ashley, Clark, Jake T, Eastman, Jason D, Ziegler, Carl, Brahm, Rafael, Carter, Bradley D, Clerte, Mathieu, Espinoza, Néstor, Horner, Jonathan, Bentley, John, Jordán, André, Kane, Stephen R, Kielkopf, John F, Laychock, Emilie, Mengel, Matthew W, Okumura, Jack, Stassun, Keivan G, Bedding, Timothy R, Bowler, Brendan P, Burnelis, Andriu, Blanco-Cuaresma, Sergi, Collins, Michaela, Crossfield, Ian, Davis, Allen B, Evensberget, Dag, Heitzmann, Alexi, Howell, Steve B, Law, Nichola, Mann, Andrew W, Marsden, Stephen C, Matson, Rachel A, O’Connor, James H, Shporer, Avi, Stevens, Catherine, Tinney, C G, Tylor, Christopher, Wang, Songhu, Zhang, Hui, Henning, Thoma, Kossakowski, Diana, Ricker, George, Sarkis, Paula, Schlecker, Martin, Torres, Pascal, Vanderspek, Roland, Latham, David W, Seager, Sara, Winn, Joshua N, Jenkins, Jon M, Mireles, Ismael, Rowden, Pam, Pepper, Joshua, Daylan, Tansu, Schlieder, Joshua E, Collins, Karen A, Collins, Kevin I, Tan, Thiam-Guan, Ball, Warrick H, Basu, Sarbani, Buzasi, Derek L, Campante, Tiago L, Corsaro, Enrico, González-Cuesta, L, Davies, Guy R, de Almeida, Leandro, do Nascimento, Jose-Dia, García, Rafael A, Guo, Zhao, Handberg, Rasmu, Hekker, Saskia, Hey, Daniel R, Kallinger, Thoma, Kawaler, Steven D, Kayhan, Cenk, S. Kuszlewicz, Jame, Lund, Mikkel N, Lyttle, Alexander, Mathur, Savita, Miglio, Andrea, Mosser, Benoit, Nielsen, Martin B, Serenelli, Aldo M, Aguirre, Victor Silva, Themeßl, Nathalie, National Aeronautics and Space Administration (US), National Science Foundation (US), Danish National Research Foundation, National Natural Science Foundation of China, Ministerio de Ciencia, Innovación y Universidades (España), Generalitat de Catalunya, European Commission, Centre National D'Etudes Spatiales (France), Ministerio de Economía y Competitividad (España), Kavli Institute for Theoretical Physics, Independent Research Fund Denmark, Carlsberg Foundation, Addison, Brett C., Wright, Duncan J., Nicholson, Belinda A., Wittenmyer, Robert A., Chaplin, William J., Clark, Jake T., Eastman, Jason D., Carter, Bradley D., Kane, Stephen R., Kielkopf, John F., Mengel, Matthew W., Stassun, Keivan G., Bedding, Timothy R., Bowler, Brendan P., Davis, Allen B., Howell, Steve B., Mann, Andrew W., Marsden, Stephen C., Matson, Rachel A., O'Connor, Jame, Tinney, C. G., Latham, David W., Winn, Joshua N., Jenkins, Jon M., Schlieder, Joshua E., Collins, Karen A., Collins, Kevin I., Ball, Warrick H., Buzasi, Derek L., Campante, Tiago L., González-Cuesta, Lucía, Davies, Guy R., do Nascimento, Jose-Dias, Jr., García, Rafael A., Hey, Daniel R., Kawaler, Steven D., Kuszlewicz, James S., Lund, Mikkel N., Nielsen, Martin B., Serenelli, Aldo M., and Silva Aguirre, Victor
Subjects: astro-ph.SR, Star (game theory), FOS: Physical sciences, Context (language use), Astrophysics, asteroseismology, Type (model theory), 01 natural sciences, Asteroseismology, spectroscopic [Techniques], techniques: photometric, stars: individual (TIC 200723869/TOI-257), 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Earth and Planetary Astrophysics (astro-ph.EP), individual (TIC 200723869/TOI-257) [Stars], radial velocities [Techniques], 010308 nuclear & particles physics, photometric [Techniques], techniques: radial velocitie, Astronomy and Astrophysics, Planetary system, planetary system, Exoplanet, Radial velocity, Stars, Planetary systems, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Techniques: radial velocities, astro-ph.EP, techniques: spectroscopic, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The transit signal was detected by TESS and confirmed to be of planetary origin based on radial velocity observations. An analysis of the TESS photometry, the Minerva-Australis, FEROS, and HARPS radial velocities, and the asteroseismic data of the stellar oscillations reveals that TOI-257b has a mass of MP = 0.138 ± 0.023 M J (43.9 ± 7.3, M⊕), a radius of RP = 0.639 ± 0.013 R J (7.16 ± 0.15, R ⊕), bulk density of 0.65+0.12-0.11 (cgs), and period 18.38818 +0.00085 -0.00084 days. TOI-257b orbits a bright (V = 7.612 mag) somewhat evolved late F-type star with M∗ = 1.390 ± 0.046 rm M sun, R∗ = 1.888 ± 0.033 Rsun, Teff = 6075 ± 90 rm K, and vsin i = 11.3 ± 0.5 km s-1. Additionally, we find hints for a second non-transiting sub-Saturn mass planet on a ∼71 day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars (∼100) that have been characterized with asteroseismology. Warm sub-Saturns are rare in the known sample of exoplanets, and thus the discovery of TOI-257b is important in the context of future work studying the formation and migration history of similar planetary systems., Daniel Huber acknowledges support by the National Aeronautics and Space Administration through the TESS Guest Investigator Program (80NSSC18K1585) and by the National Science Foundation (AST-1717000). Ashley Chontos acknowledges support from the National Science Foundation through the Graduate Research Fellowship Program (DGE 1842402). William J. Chaplin, Warrick H. Ball, Martin B. Nielsen, and Andrea Miglio. acknowledge support from the Science and Technology Facilities Council and UK Space Agency. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant DNRF106). Rafael Brahm acknowledges support from National Fund for Scientific and Technological Development Post-doctoral Fellowship Project 3180246, and from the Millennium Institute of Astrophysics (MAS). H.Z. Hui Zhang is supported by the Natural Science Foundation of China (NSFC grants 11673011, 11933001). Andres Jordan acknowledges support from FONDECYT project 1171208 and by the Ministry for the Economy, Development, and Tourism’s Programa Iniciativa Científica Milenio through grant IC 120009, awarded to the Millennium Institute of Astrophysics (MAS). Aldo M. Serenelli is partially supported by grants ESP2017-82674-R (Spanish Government) and 2017-SGR-1131 (Generalitat de Catalunya). Andrea Miglio acknowledges support from the European Research Council Consolidator Grant funding scheme (project ASTEROCHRONOMETRY, G.A. number 772293). Rafael A. Garcia acknowledges the support of the PLAnetary Transits and Oscillations of stars grant from the Centre National d'Études Spatiales. Savita Mathur acknowledges support from the Spanish Ministry with the Ramon y Cajal fellowship number RYC-2015-17697. Tiago L. Campante acknowledges support from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 792848 (PULSATION). This work was supported by Foundation of Science and Technology/Ministry of Science, Technology and Higher Education through national funds (UID/FIS/04434/2019). Enrico Corsaro is funded by the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 664931. L. González-Cuesta thanks the support from grant FPI-SO from the Spanish Ministry of Economy and Competitiveness (MINECO) (research project SEV-2015-0548-17-2 and predoctoral contract BES-2017-082610). Sarbani Basu acknowledges NASA grant NNX16AI09G and NSF grant AST-1514676. Ian J. M. Crossfield acknowledges support from the NSF through grant AST-1824644, and from NASA through Caltech/JPL grant RSA-1610091. Tansu Daylan acknowledges support from MIT’s Kavli Institute as a Kavli postdoctoral fellow. Derek L. Buzasi acknowledges support from NASA through the TESS Guest Investigator program (80NSSC19K0385). Cenk Kayhan acknowledges support by Erciyes University Scientific Research Projects Coordination Unit under grant number MAP-2020-9749. Emilie Laychock and Michaela Collins acknowledge support by the National Science Foundation under grant 1559487. Victor Silva Aguirre acknowledges support from the Independent Research Fund Denmark (Research grant 7027-00096B) and the Carlsberg Foundation (grant agreement CF19-0649).
Published: 2020
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46. KELT-25b and KELT-26b: A Hot Jupiter and a Substellar Companion Transiting Young A-stars Observed by TESS

Author: Max Günther, Joshua Pepper, Dennis M. Conti, L. A. Paredes, Robert J. Siverd, Rachel A. Matson, Jonathan Horner, Jeffrey D. Crane, David J. James, Steven Villanueva, Roberto Zambelli, Sharon X. Wang, Stephen A. Shectman, Darren L. DePoy, Steve B. Howell, Roland Vanderspek, David W. Latham, Daniel J. Stevens, Jennifer L. Marshall, Romy Rodríguez Martínez, Mark E. Everett, Keivan G. Stassun, Elisa V. Quintana, Matthew W. Mengel, Andrei Tokovinin, Mark Trueblood, Sara Seager, David H. Cohen, Luke G. Bouma, Eric B. Ting, Marshall C. Johnson, John F. Kielkopf, Daniel Bayliss, Jon M. Jenkins, Samuel N. Quinn, Knicole D. Colón, Mark Manner, Denise C. Stephens, Howard M. Relles, Eric L. N. Jensen, David R. Ciardi, Joshua N. Winn, Michael D. Joner, Thiam-Guan Tan, George Zhou, Allyson Bieryla, Ian B. Thompson, Matthew T. Penny, Karen A. Collins, Diana Dragomir, Jason Rothenberg, Wei-Chun Jao, Phillip A. Cargile, Hodari-Sadiki James, Hui Zhang, Phillip A. Reed, B. Scott Gaudi, Thomas G. Beatty, Pat Trueblood, Rudolf B. Kuhn, Kaloyan Penev, Ana Glidden, Joao Gregorio, Timothy R. Bedding, Andrew W. Mann, Johanna Teske, Coleman Kilby, J. Labadie-Bartz, Somayeh Khakpash, Nicholas J. Scott, Phil Evans, Brett C. Addison, Joseph E. Rodriguez, Jack Okumura, Carl Ziegler, Stephen R. Kane, Xinyu Yao, Paul Butler, Duncan J. Wright, Robert A. Wittenmyer, Dax L. Feliz, Michael B. Lund, Chris Stockdale, C. G. Tinney, Todd J. Henry, Michael Fausnaugh, Timothy D. Morton, Peter Plavchan, Ivan A. Curtis, Jason D. Eastman, Kim K. McLeod, and Brendan P. Bowler
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Am star, Light curve, 01 natural sciences, Exoplanet, Radial velocity, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, 0103 physical sciences, Hot Jupiter, 010303 astronomy & astrophysics, Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the discoveries of KELT-25b (TIC 65412605, TOI-626.01) and KELT-26b (TIC 160708862, TOI-1337.01), two transiting companions orbiting relatively bright, early A-stars. The transit signals were initially detected by the KELT survey, and subsequently confirmed by \textit{TESS} photometry. KELT-25b is on a 4.40-day orbit around the V = 9.66 star CD-24 5016 ($T_{\rm eff} = 8280^{+440}_{-180}$ K, $M_{\star}$ = $2.18^{+0.12}_{-0.11}$ $M_{\odot}$), while KELT-26b is on a 3.34-day orbit around the V = 9.95 star HD 134004 ($T_{\rm eff}$ =$8640^{+500}_{-240}$ K, $M_{\star}$ = $1.93^{+0.14}_{-0.16}$ $M_{\odot}$), which is likely an Am star. We have confirmed the sub-stellar nature of both companions through detailed characterization of each system using ground-based and \textit{TESS} photometry, radial velocity measurements, Doppler Tomography, and high-resolution imaging. For KELT-25, we determine a companion radius of $R_{\rm P}$ = $1.64^{+0.039}_{-0.043}$ $R_{\rm J}$, and a 3-sigma upper limit on the companion's mass of $\sim64~M_{\rm J}$. For KELT-26b, we infer a planetary mass and radius of $M_{\rm P}$ = $1.41^{+0.43}_{-0.51}$ $M_{\rm J}$ and $R_{\rm P}$ = $1.940^{+0.060}_{-0.058}$ $R_{\rm J}$. From Doppler Tomographic observations, we find KELT-26b to reside in a highly misaligned orbit. This conclusion is weakly corroborated by a subtle asymmetry in the transit light curve from the \textit{TESS} data. KELT-25b appears to be in a well-aligned, prograde orbit, and the system is likely a member of a cluster or moving group., 24 pages, 18 figures, 8 tables
Published: 2019

47. Distance Learning Support of Hypertension Self-Management

Author: Amisha S, Oza, primary, Diane M, Welsh, additional, Kim, Chapman, additional, Rachel, Koransky-Matson, additional, and Natasha Jno, Baptiste, additional
Published: 2020
Full Text: View/download PDF

48. Speckle Interferometry at the U.S. Naval Observatory. XXIV

Author: Jordan D. Josties, Phillip D. Eakens, Rich Warner, Brian D. Mason, Rachel A. Matson, Mark Justice, Stephen J. Williams, and Christopher M. Kilian
Subjects: Physics, Space and Planetary Science, Observatory, Binary star, Astronomy, Astronomy and Astrophysics, Speckle imaging
Abstract: The results of 3611 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each observation of a system represents a combination of over 2000 short-exposure images. These observations are averaged into 1857 mean relative positions and range in separation from 0.″341 to 128.″644, with a median separation of 6.″533. Two systems have their orbits improved and one has its first determination. This is the 24th in this series of papers and covers the period 2018 May 24 through 2019 October 28.
Published: 2021

49. A super-Earth and sub-Neptune transiting the late-type M dwarf LP 791-18

Author: Adam L. Kraus, Nicholas J. Scott, Jonathan Irwin, Jennifer Burt, Nicholas Mehrle, David W. Latham, Elisabeth Matthews, Joshua E. Schlieder, David Berardo, Joshua N. Winn, Karen A. Collins, Samuel Halverson, Chelsea X. Huang, Kristo Ment, Stephen R. Kane, Masayuki Kuzuhara, Ian J. M. Crossfield, Teruyuki Hirano, William Waalkes, Elisa V. Quintana, Jennifer G. Winters, Diana Dragomir, Takayuki Kotani, Daniel Huber, Noriharu Watanabe, Motohide Tamura, Erica J. Gonzales, Mark E. Everett, Ashley Chontos, Rachel A. Matson, David Charbonneau, Erik A. Petigura, Knicole D. Colón, Thomas Mikal-Evans, Paul A. Dalba, Douglas A. Caldwell, Björn Benneke, Joseph D. Twicken, Norio Narita, Howard Isaacson, Trent J. Dupuy, Molly R. Kosiarek, George R. Ricker, Merrin Peterson, Bárbara Rojas-Ayala, Andrew W. Howard, Courtney D. Dressing, Jon M. Jenkins, Sébastien Lépine, Benjamin J. Fulton, Steve B. Howell, Elisabeth R. Newton, Zachory K. Berta-Thompson, Veselin B. Kostov, Philip S. Muirhead, Sara Seager, Yasunori Hori, Aaron C. Rizzuto, Mark E. Rose, and Teo Mocnik
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Super-Earth, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Effective temperature, Ephemeris, 01 natural sciences, Exoplanet, Radial velocity, Stars, 13. Climate action, Space and Planetary Science, Neptune, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: Planets occur most frequently around cool dwarfs, but only a handful of specific examples are known to orbit the latest-type M stars. Using TESS photometry, we report the discovery of two planets transiting the low-mass star called LP 791-18 (identified by TESS as TOI 736). This star has spectral type M6V, effective temperature 2960 K, and radius 0.17 R_Sun, making it the third-coolest star known to host planets. The two planets straddle the radius gap seen for smaller exoplanets; they include a 1.1 R_Earth planet on a 0.95 day orbit and a 2.3 R_Earth planet on a 5 day orbit. Because the host star is small the loss of light during these planets' transits is fairly large (0.4% and 1.7%). This has allowed us to detect both planets' transits from ground-based photometry, refining their radii and orbital ephemerides. In the future, radial velocity observations and transmission spectroscopy can both probe these planets' bulk interior and atmospheric compositions, and additional photometric monitoring would be sensitive to even smaller transiting planets., 20 pages, 7 figures, 2 tables, 2 planets, 1 cool star. Submitted to AAS Journals
Published: 2019

50. TOI-150b and TOI-163b: two transiting hot Jupiters, one eccentric and one inflated, revealed by TESS near and at the edge of the JWST CVZ

Author: Thomas Henning, Chris Stockdale, Diana Kossakowski, Maxime Marmier, Rachel A. Matson, Joshua E. Schlieder, Edward H. Morgan, Vincent Suc, Jeffrey C. Smith, Jie Li, Joshua N. Winn, Francisco J. Pozuelos, Gáspár Á. Bakos, Jon M. Jenkins, Elliott P. Horch, Eric L. N. Jensen, Stéphane Udry, Michaël Gillon, Néstor Espinoza, Rafael Brahm, Waqas Bhatti, Erica J. Gonzales, David R. Ciardi, Emmanuel Jehin, Damien Ségransan, Liang Yu, Elisabeth Matthews, Karen A. Collins, Martin Kürster, George R. Ricker, Martin Schlecker, Francesco Pepe, Khalid Barkaoui, Phil Evans, Andrés Jordán, Sara Seager, Avi Shporer, J. Villasenor, David J. Osip, Steve B. Howell, Paula Sarkis, Kevin I. Collins, Christophe Lovis, Howard M. Relles, Mark E. Rose, Ian J. M. Crossfield, Z. Csubry, Oliver Turner, Felipe Rojas, Tess R. Jaffe, David Charbonneau, Scott Dynes, François Bouchy, and Louise D. Nielsen
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), James Webb Space Telescope, FOS: Physical sciences, Astronomy and Astrophysics, Orbital eccentricity, 02 engineering and technology, Astrophysics, 021001 nanoscience & nanotechnology, 01 natural sciences, Exoplanet, Radial velocity, Photometry (optics), Stars, Space and Planetary Science, Planet, 0103 physical sciences, Hot Jupiter, 0210 nano-technology, 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the discovery of TYC9191-519-1b (TOI-150b, TIC 271893367) and HD271181b (TOI-163b, TIC 179317684), two hot Jupiters initially detected using 30-minute cadence Transiting Exoplanet Survey Satellite TESS photometry from Sector 1 and thoroughly characterized through follow-up photometry (CHAT, Hazelwood, LCO/CTIO, El Sauce, TRAPPIST-S), high-resolution spectroscopy (FEROS, CORALIE) and speckle imaging (Gemini/DSSI), confirming the planetary nature of the two signals. A simultaneous joint fit of photometry and radial velocity using a new fitting package juliet reveals that TOI-150b is a $1.254\pm0.016\ R_J$, massive ($2.61^{+0.19}_{-0.12}\ M_J$) hot Jupiter in a $5.857$-day orbit, while TOI-163b is an inflated ($R_P$ = $1.478^{+0.022}_{-0.029} R_J$, $M_P$ = $1.219\pm0.11 M_J$) hot Jupiter on a $P$ = $4.231$-day orbit; both planets orbit F-type stars. A particularly interesting result is that TOI-150b shows an eccentric orbit ($e=0.262^{+0.045}_{-0.037}$), which is quite uncommon among hot Jupiters. We estimate that this is consistent, however, with the circularization timescale which is slightly larger than the age of the system. These two hot Jupiters are both prime candidates for further characterization --- in particular, both are excellent candidates for determining spin-orbit alignments via the Rossiter-McLaughlin (RM) effect and for characterizing atmospheric thermal structures using secondary eclipse observations considering they are both located closely to the James Webb Space Telescope (JWST) Continuous Viewing Zone (CVZ)., referee report submitted to MNRAS
Published: 2019

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