Search

Your search keyword '"Jensen ELN"' showing total 8 results
Start Over Author "Jensen ELN" Language english
8 results on '"Jensen ELN"'

1. 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
Full Text
View/download PDF

2. 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
Full Text
View/download PDF

3. Author Correction: A super-massive Neptune-sized planet.

Author

Naponiello L, Mancini L, Sozzetti A, Bonomo AS, Morbidelli A, Dou J, Zeng L, Leinhardt ZM, Biazzo K, Cubillos PE, Pinamonti M, Locci D, Maggio A, Damasso M, Lanza AF, Lissauer JJ, Collins KA, Carter PJ, Jensen ELN, Bignamini A, Boschin W, Bouma LG, Ciardi DR, Cosentino R, Crossfield I, Desidera S, Dumusque X, Fiorenzano AFM, Fukui A, Giacobbe P, Gnilka CL, Ghedina A, Guilluy G, Harutyunyan A, Howell SB, Jenkins JM, Lund MB, Kielkopf JF, Lester KV, Malavolta L, Mann AW, Matson RA, Matthews EC, Nardiello D, Narita N, Pace E, Pagano I, Palle E, Pedani M, Seager S, Schlieder JE, Schwarz RP, Shporer A, Twicken JD, Winn JN, Ziegler C, and Zingales T

Published
2023
Full Text
View/download PDF

4. A super-massive Neptune-sized planet.

Author

Naponiello L, Mancini L, Sozzetti A, Bonomo AS, Morbidelli A, Dou J, Zeng L, Leinhardt ZM, Biazzo K, Cubillos PE, Pinamonti M, Locci D, Maggio A, Damasso M, Lanza AF, Lissauer JJ, Collins KA, Carter PJ, Jensen ELN, Bignamini A, Boschin W, Bouma LG, Ciardi DR, Cosentino R, Crossfield I, Desidera S, Dumusque X, Fiorenzano AFM, Fukui A, Giacobbe P, Gnilka CL, Ghedina A, Guilluy G, Harutyunyan A, Howell SB, Jenkins JM, Lund MB, Kielkopf JF, Lester KV, Malavolta L, Mann AW, Matson RA, Matthews EC, Nardiello D, Narita N, Pace E, Pagano I, Palle E, Pedani M, Seager S, Schlieder JE, Schwarz RP, Shporer A, Twicken JD, Winn JN, Ziegler C, and Zingales T

Abstract

Neptune-sized planets exhibit a wide range of compositions and densities, depending on factors related to their formation and evolution history, such as the distance from their host stars and atmospheric escape processes. They can vary from relatively low-density planets with thick hydrogen-helium atmospheres 1,2 to higher-density planets with a substantial amount of water or a rocky interior with a thinner atmosphere, such as HD 95338 b (ref.  3 ), TOI-849 b (ref.  4 ) and TOI-2196 b (ref.  5 ). The discovery of exoplanets in the hot-Neptune desert 6 , a region close to the host stars with a deficit of Neptune-sized planets, provides insights into the formation and evolution of planetary systems, including the existence of this region itself. Here we show observations of the transiting planet TOI-1853 b, which has a radius of 3.46 ± 0.08 Earth radii and orbits a dwarf star every 1.24 days. This planet has a mass of 73.2 ± 2.7 Earth masses, almost twice that of any other Neptune-sized planet known so far, and a density of 9.7 ± 0.8 grams per cubic centimetre. These values place TOI-1853 b in the middle of the Neptunian desert and imply that heavy elements dominate its mass. The properties of TOI-1853 b present a puzzle for conventional theories of planetary formation and evolution, and could be the result of several proto-planet collisions or the final state of an initially high-eccentricity planet that migrated closer to its parent star., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Published
2023
Full Text
View/download PDF

5. A temperate Earth-sized planet with tidal heating transiting an M6 star.

Author

Peterson MS, Benneke B, Collins K, Piaulet C, Crossfield IJM, Ali-Dib M, Christiansen JL, Gagné J, Faherty J, Kite E, Dressing C, Charbonneau D, Murgas F, Cointepas M, Almenara JM, Bonfils X, Kane S, Werner MW, Gorjian V, Roy PA, Shporer A, Pozuelos FJ, Socia QJ, Cloutier R, Dietrich J, Irwin J, Weiss L, Waalkes W, Berta-Thomson Z, Evans T, Apai D, Parviainen H, Pallé E, Narita N, Howard AW, Dragomir D, Barkaoui K, Gillon M, Jehin E, Ducrot E, Benkhaldoun Z, Fukui A, Mori M, Nishiumi T, Kawauchi K, Ricker G, Latham DW, Winn JN, Seager S, Isaacson H, Bixel A, Gibbs A, Jenkins JM, Smith JC, Chavez JP, Rackham BV, Henning T, Gabor P, Chen WP, Espinoza N, Jensen ELN, Collins KI, Schwarz RP, Conti DM, Wang G, Kielkopf JF, Mao S, Horne K, Sefako R, Quinn SN, Moldovan D, Fausnaugh M, Fűűrész G, and Barclay T

Abstract

Temperate Earth-sized exoplanets around late-M dwarfs offer a rare opportunity to explore under which conditions planets can develop hospitable climate conditions. The small stellar radius amplifies the atmospheric transit signature, making even compact secondary atmospheres dominated by N 2 or CO 2 amenable to characterization with existing instrumentation 1 . Yet, despite large planet search efforts 2 , detection of low-temperature Earth-sized planets around late-M dwarfs has remained rare and the TRAPPIST-1 system, a resonance chain of rocky planets with seemingly identical compositions, has not yet shown any evidence of volatiles in the system 3 . Here we report the discovery of a temperate Earth-sized planet orbiting the cool M6 dwarf LP 791-18. The newly discovered planet, LP 791-18d, has a radius of 1.03 ± 0.04 R ⊕ and an equilibrium temperature of 300-400 K, with the permanent night side plausibly allowing for water condensation. LP 791-18d is part of a coplanar system 4 and provides a so-far unique opportunity to investigate a temperate exo-Earth in a system with a sub-Neptune that retained its gas or volatile envelope. On the basis of observations of transit timing variations, we find a mass of 7.1 ± 0.7 M ⊕ for the sub-Neptune LP 791-18c and a mass of [Formula: see text] for the exo-Earth LP 791-18d. The gravitational interaction with the sub-Neptune prevents the complete circularization of LP 791-18d's orbit, resulting in continued tidal heating of LP 791-18d's interior and probably strong volcanic activity at the surface 5,6 ., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Published
2023
Full Text
View/download PDF

6. A nearby transiting rocky exoplanet that is suitable for atmospheric investigation.

Author

Trifonov T, Caballero JA, Morales JC, Seifahrt A, Ribas I, Reiners A, Bean JL, Luque R, Parviainen H, Pallé E, Stock S, Zechmeister M, Amado PJ, Anglada-Escudé G, Azzaro M, Barclay T, Béjar VJS, Bluhm P, Casasayas-Barris N, Cifuentes C, Collins KA, Collins KI, Cortés-Contreras M, de Leon J, Dreizler S, Dressing CD, Esparza-Borges E, Espinoza N, Fausnaugh M, Fukui A, Hatzes AP, Hellier C, Henning T, Henze CE, Herrero E, Jeffers SV, Jenkins JM, Jensen ELN, Kaminski A, Kasper D, Kossakowski D, Kürster M, Lafarga M, Latham DW, Mann AW, Molaverdikhani K, Montes D, Montet BT, Murgas F, Narita N, Oshagh M, Passegger VM, Pollacco D, Quinn SN, Quirrenbach A, Ricker GR, Rodríguez López C, Sanz-Forcada J, Schwarz RP, Schweitzer A, Seager S, Shporer A, Stangret M, Stürmer J, Tan TG, Tenenbaum P, Twicken JD, Vanderspek R, and Winn JN

Abstract

Spectroscopy of transiting exoplanets can be used to investigate their atmospheric properties and habitability. Combining radial velocity (RV) and transit data provides additional information on exoplanet physical properties. We detect a transiting rocky planet with an orbital period of 1.467 days around the nearby red dwarf star Gliese 486. The planet Gliese 486 b is 2.81 Earth masses and 1.31 Earth radii, with uncertainties of 5%, as determined from RV data and photometric light curves. The host star is at a distance of ~8.1 parsecs, has a J -band magnitude of ~7.2, and is observable from both hemispheres of Earth. On the basis of these properties and the planet's short orbital period and high equilibrium temperature, we show that this terrestrial planet is suitable for emission and transit spectroscopy., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Published
2021
Full Text
View/download PDF

7. A remnant planetary core in the hot-Neptune desert.

Author

Armstrong DJ, Lopez TA, Adibekyan V, Booth RA, Bryant EM, Collins KA, Deleuil M, Emsenhuber A, Huang CX, King GW, Lillo-Box J, Lissauer JJ, Matthews E, Mousis O, Nielsen LD, Osborn H, Otegi J, Santos NC, Sousa SG, Stassun KG, Veras D, Ziegler C, Acton JS, Almenara JM, Anderson DR, Barrado D, Barros SCC, Bayliss D, Belardi C, Bouchy F, Briceño C, Brogi M, Brown DJA, Burleigh MR, Casewell SL, Chaushev A, Ciardi DR, Collins KI, Colón KD, Cooke BF, Crossfield IJM, Díaz RF, Mena ED, Demangeon ODS, Dorn C, Dumusque X, Eigmüller P, Fausnaugh M, Figueira P, Gan T, Gandhi S, Gill S, Gonzales EJ, Goad MR, Günther MN, Helled R, Hojjatpanah S, Howell SB, Jackman J, Jenkins JS, Jenkins JM, Jensen ELN, Kennedy GM, Latham DW, Law N, Lendl M, Lozovsky M, Mann AW, Moyano M, McCormac J, Meru F, Mordasini C, Osborn A, Pollacco D, Queloz D, Raynard L, Ricker GR, Rowden P, Santerne A, Schlieder JE, Seager S, Sha L, Tan TG, Tilbrook RH, Ting E, Udry S, Vanderspek R, Watson CA, West RG, Wilson PA, Winn JN, Wheatley P, Villasenor JN, Vines JI, and Zhan Z

Abstract

The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune 'desert' 1,2 (a region in mass-radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b 3 , which is thought to have an unusually massive core, and recent discoveries such as LTT9779b 4 and NGTS-4b 5 , on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune's but an anomalously large mass of [Formula: see text] Earth masses and a density of [Formula: see text] grams per cubic centimetre, similar to Earth's. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than [Formula: see text] per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation 6 . Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.

Published
2020
Full Text
View/download PDF

8. A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host.

Author

Gaudi BS, Stassun KG, Collins KA, Beatty TG, Zhou G, Latham DW, Bieryla A, Eastman JD, Siverd RJ, Crepp JR, Gonzales EJ, Stevens DJ, Buchhave LA, Pepper J, Johnson MC, Colon KD, Jensen ELN, Rodriguez JE, Bozza V, Novati SC, D'Ago G, Dumont MT, Ellis T, Gaillard C, Jang-Condell H, Kasper DH, Fukui A, Gregorio J, Ito A, Kielkopf JF, Manner M, Matt K, Narita N, Oberst TE, Reed PA, Scarpetta G, Stephens DC, Yeigh RR, Zambelli R, Fulton BJ, Howard AW, James DJ, Penny M, Bayliss D, Curtis IA, DePoy DL, Esquerdo GA, Gould A, Joner MD, Kuhn RB, Labadie-Bartz J, Lund MB, Marshall JL, McLeod KK, Pogge RW, Relles H, Stockdale C, Tan TG, Trueblood M, and Trueblood P

Abstract

The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300-10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref. 1); the planet is itself as hot as a red dwarf star of type M (ref. 2). WASP-33b displays a large heat differential between its dayside and nightside, and is highly inflated-traits that have been linked to high insolation. However, even at the temperature of its dayside, its atmosphere probably resembles the molecule-dominated atmospheres of other planets and, given the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be substantially ablated over the lifetime of its star. Here we report observations of the bright star HD 195689 (also known as KELT-9), which reveal a close-in (orbital period of about 1.48 days) transiting giant planet, KELT-9b. At approximately 10,170 kelvin, the host star is at the dividing line between stars of type A and B, and we measure the dayside temperature of KELT-9b to be about 4,600 kelvin. This is as hot as stars of stellar type K4 (ref. 5). The molecules in K stars are entirely dissociated, and so the primary sources of opacity in the dayside atmosphere of KELT-9b are probably atomic metals. Furthermore, KELT-9b receives 700 times more extreme-ultraviolet radiation (that is, with wavelengths shorter than 91.2 nanometres) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star.

Published
2017
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results