Search

We present the discovery and characterization of six short-period, transiting giant planets from NASA's Transiting Exoplanet Survey Satellite (TESS) -- TOI-1811 (TIC 376524552), TOI-2025 (TIC 394050135), TOI-2145 (TIC 88992642), TOI-2152 (TIC 395393265), TOI-2154 (TIC 428787891), & TOI-2497 (TIC 97568467). All six planets orbit bright host stars (8.9, Comment: 20 Pages, 6 Figures, 8 Tables, Accepted by MNRAS

We report on the discovery of an Earth-sized transiting planet ($R_p=1.015\pm0.051\,R_\oplus$) in a $P=4.02$ day orbit around K2-415 (EPIC 211414619), an M5V star at 22 pc. The planet candidate was first identified by analyzing the light curve data by the K2 mission, and is here shown to exist in the most recent data from TESS. Combining the light curves with the data secured by our follow-up observations including high-resolution imaging and near infrared spectroscopy with IRD, we rule out false positive scenarios, finding a low false positive probability of $2\times 10^{-4}$. Based on IRD's radial velocities of K2-415, which were sparsely taken over three years, we obtain the planet mass of $3.0\pm 2.7\,M_\oplus$ ($M_p, 20 pages, 12 figures, accepted for publication in AJ

The Subaru telescope is currently performing a strategic program (SSP) using the high-precision near-infrared (NIR) spectrometer IRD to search for exoplanets around nearby mid/late-M~dwarfs via radial velocity (RV) monitoring. As part of the observing strategy for the exoplanet survey, signatures of massive companions such as RV trends are used to reduce the priority of those stars. However, this RV information remains useful for studying the stellar multiplicity of nearby M~dwarfs. To search for companions around such ``deprioritized" M~dwarfs, we observed 14 IRD-SSP targets using Keck/NIRC2 observations with pyramid wavefront sensing at NIR wavelengths, leading to high sensitivity to substellar-mass companions within a few arcseconds. We detected two new companions (LSPM~J1002+1459~B and LSPM~J2204+1505~B) and two new candidates that are likely companions (LSPM~J0825+6902~B and LSPM~J1645+0444~B) as well as one known companion. Including two known companions resolved by the IRD fiber injection module camera, we detected seven (four new) companions at projected separations between $\sim2-20$~au in total. A comparison of the colors with the spectral library suggests that LSPM~J2204+1505~B and LSPM~J0825+6902~B are located at the boundary between late-M and early-L spectral types. Our deep high-contrast imaging for targets where no bright companions were resolved did not reveal any additional companion candidates. The NIRC2 detection limits could constrain potential substellar-mass companions ($\sim10-75\ M_{\rm Jup}$) at 10~au or further. The failure with Keck/NIRC2 around the IRD-SSP stars having significant RV trends makes these objects promising targets for further RV monitoring or deeper imaging with JWST to search for smaller-mass companions below the NIRC2 detection limits., 16 pages, 8 figures, accepted for publication in AJ

TOI-640 b is a hot, puffy Jupiter with a mass of $0.57 \pm 0.02$ M$_{\rm J}$ and radius of $1.72 \pm 0.05$ R$_{\rm J}$, orbiting a slightly evolved F-type star with a separation of $6.33^{+0.07}_{-0.06}$ R$_\star$. Through spectroscopic in-transit observations made with the HARPS spectrograph, we measured the Rossiter-McLaughlin effect, analysing both in-transit radial velocities and the distortion of the stellar spectral lines. From these observations, we find the host star to have a projected obliquity of $\lambda=184\pm3^\circ$. From the TESS light curve, we measured the stellar rotation period, allowing us to determine the stellar inclination, $i_\star=23^{+3\circ}_{-2}$, meaning we are viewing the star pole-on. Combining this with the orbital inclination allowed us to calculate the host star obliquity, $\psi=104\pm2^\circ$. TOI-640 b joins a group of planets orbiting over stellar poles within the range $80^\circ-125^\circ$. The origin of this orbital configuration is not well understood., Comment: 15 pages, 12 figures, accepted for publication in A&A, in press

Remote sensing of the Earth has demonstrated that photosynthesis is traceable as the vegetation red edge (VRE), which is a steep rise in the reflection spectrum of vegetation, and as solar-induced fluorescence. This study examines the detectability of biological fluorescence from two types of photosynthetic pigments, chlorophylls (Chls) and bacteriochlorophylls (BChls), on Earthlike planets with oxygen-rich/poor and anoxic atmospheres around the Sun and M dwarfs. Atmospheric absorption, such as H2O, CH4, O2, and O3, and the VRE obscure the fluorescence emissions from Chls and BChls. We find that the BChl-based fluorescence for wavelengths of 1000–1100 nm, assuming the spectrum of BChl b–bearing purple bacteria, could provide a suitable biosignature, but only in the absence of water cloud coverage or other strong absorbers near 1000 nm. The Chl fluorescence is weaker for several reasons, e.g., spectral blending with the VRE. The apparent reflectance excess is greatly increased in both the Chl and BChl cases around TRAPPIST-1, due to the fluorescence and stellar absorption lines. This could be a promising feature for detecting the fluorescence around ultracool red dwarfs using follow-up ground-based observations at high spectral resolution; however, this would require a long time around Sunlike stars, even for a LUVOIR-like space mission. Moreover, the simultaneous detection of fluorescence and the VRE is the key to identifying traces of photosynthesis, because absorption, reflectance, and fluorescence are physically connected. For further validation of the fluorescence detection, the nonlinear response of biological fluorescence as a function of light intensity could be considered.

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

We report the discovery of TOI-2119b, a transiting brown dwarf (BD) that orbits and is completely eclipsed by an active M-dwarf star. Using light curve data from the Transiting Exoplanet Survey Satellite mission and follow-up high-resolution Doppler spectroscopic observations, we find the BD has a radius of $R_b = 1.08 \pm 0.03{\rm R_J}$, a mass of $M_b = 64.4 \pm 2.3{\rm M_J}$, an orbital period of $P = 7.200865 \pm 0.00002$ days, and an eccentricity of $e=0.337\pm 0.002$. The host star has a mass of $M_\star = 0.53 \pm 0.02{\rm M_\odot}$, a radius of $R_\star= 0.50 \pm 0.01{\rm R_\odot}$, an effective temperature of $T_{\rm eff} = 3621 \pm 48$K, and a metallicity of $\rm [Fe/H]=+0.06\pm 0.08$. TOI-2119b joins an emerging population of transiting BDs around M-dwarf host stars, with TOI-2119 being the ninth such system. These M-dwarf--brown dwarf systems typically occupy mass ratios near $q = M_b/M_\star \approx 0.1-0.2$, which separates them from the typical mass ratios for systems with transiting substellar objects and giant exoplanets that orbit more massive stars. The nature of the secondary eclipse of the BD by the star enables us to estimate the effective temperature of the substellar object to be $2030\pm 84$K, which is consistent with predictions by substellar evolutionary models., Comment: 14 pages, 13 figures, 4 tables, accepted in MNRAS

HIP 41378 f is a temperate $9.2\pm0.1 R_{\oplus}$ planet with period of 542.08 days and an extremely low density of $0.09\pm0.02$ g cm$^{-3}$. It transits the bright star HIP 41378 (V=8.93), making it an exciting target for atmospheric characterization including transmission spectroscopy. HIP 41378 was monitored photometrically between the dates of 2019 November 19 and November 28. We detected a transit of HIP 41378 f with NGTS, just the third transit ever detected for this planet, which confirms the orbital period. This is also the first ground-based detection of a transit of HIP 41378 f. Additional ground-based photometry was also obtained and used to constrain the time of the transit. The transit was measured to occur 1.50 hours earlier than predicted. We use an analytic transit timing variation (TTV) model to show the observed TTV can be explained by interactions between HIP 41378 e and HIP 41378 f. Using our TTV model, we predict the epochs of future transits of HIP 41378 f, with derived transit centres of T$_{C,4} = 2459355.087^{+0.031}_{-0.022}$ (May 2021) and T$_{C,5} = 2459897.078^{+0.114}_{-0.060}$ (Nov 2022)., Comment: Accepted for publication in MNRAS Letters. 6 pages, 2 figures

Full list of authors: Reefe, Michael A.; Luque, Rafael; Gaidos, Eric; Beard, Corey; Plavchan, Peter P.; Cointepas, Marion; Cale, Bryson L.; Palle, Enric; Parviainen, Hannu; Feliz, Dax L.; Eastman, Jason; Stassun, Keivan; Gagné, Jonathan; Jenkins, Jon M.; Boyd, Patricia T.; Kidwell, Richard C.; McDermott, Scott; Collins, Karen A.; Fong, William; Guerrero, Natalia; Almenara-Villa, Jose-Manuel; Bean, Jacob; Beichman, Charles A.; Berberian, John; Bieryla, Allyson; Bonfils, Xavier; Bouchy, François; Brady, Madison; Bryant, Edward M.; Cacciapuoti, Luca; Cañas, Caleb I.; Ciardi, David R.; Collins, Kevin I.; Crossfield, Ian J. M.; Dressing, Courtney D.; Eigmüller, Philipp; El Mufti, Mohammed; Esparza-Borges, Emma; Fukui, Akihiko; Gao, Peter; Geneser, Claire; Gnilka, Crystal L.; Gonzales, Erica; Gupta, Arvind F.; Halverson, Sam; Hearty, Fred; Howell, Steve B.; Irwin, Jonathan; Kanodia, Shubham; Kasper, David; Kodama, Takanori; Kostov, Veselin; Latham, David W.; Lendl, Monika; Lin, Andrea; Livingston, John H.; Lubin, Jack; Mahadevan, Suvrath; Matson, Rachel; Matthews, Elisabeth; Murgas, Felipe; Narita, Norio; Newman, Patrick; Ninan, Joe; Osborn, Ares; Quinn, Samuel N.; Robertson, Paul; Roy, Arpita; Schlieder, Joshua; Schwab, Christian; Seifahrt, Andreas; Smith, Gareth D.; Sohani, Ahmad; Stefánsson, Guðmundur; Stevens, Daniel; Stürmer, Julian; Tanner, Angelle; Terrien, Ryan; Teske, Johanna; Vermilion, David; Wang, Sharon X.; Wittrock, Justin; Wright, Jason T.; Zechmeister, Mathias; Zohrabi, Farzaneh.--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., We present the validation of a transiting low-density exoplanet orbiting the M2.5 dwarf TOI 620 discovered by the NASA Transiting Exoplanet Survey Satellite (TESS) mission. We utilize photometric data from both TESS and ground-based follow-up observations to validate the ephemerides of the 5.09 day transiting signal and vet false-positive scenarios. High-contrast imaging data are used to resolve the stellar host and exclude stellar companions at separations ≳0farcs2. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with multiple precision radial velocity (PRV) spectrographs to confirm the planetary nature of the transiting exoplanet. We calculate a 5σ upper limit of MP < 7.1 M⊕ and ρP < 0.74 g cm−3, and we identify a nontransiting 17.7 day candidate. We also find evidence for a substellar (1–20 MJ) companion with a projected separation ≲20 au from a combined analysis of Gaia, adaptive optics imaging, and RVs. With the discovery of this outer companion, we carry out a detailed exploration of the possibilities that TOI 620 b might instead be a circum-secondary planet or a pair of eclipsing binary stars orbiting the host in a hierarchical triple system. We find, under scrutiny, that we can exclude both of these scenarios from the multiwavelength transit photometry, thus validating TOI 620 b as a low-density exoplanet transiting the central star in this system. The low density of TOI 620 b makes it one of the most amenable exoplanets for atmospheric characterization, such as with the James Webb Space Telescope and Ariel, validated or confirmed by the TESS mission to date. © 2022. The Author(s). Published by the American Astronomical Society., M.A.R. and P.P.P. acknowledge support from NASA (Exoplanet Research Program Award #80NSSC20K0251, TESS Cycle 3 Guest Investigator Program Award #80NSSC21K0349, JPL Research and Technology Development, and Keck Observatory Data Analysis) and the NSF (Astronomy and Astrophysics grant Nos. 1716202 and 2006517), and the Mt Cuba Astronomical Foundation. R.L. acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación, through project PID2019-109522GB-C52, and the Centre of Excellence "Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This work is partly supported by JSPS KAKENHI grant No. P17H04574, JP18H05439, JP20K14518, JP21K13975, JST CREST grant No. JPMJCR1761, and the Astrobiology Center of National Institutes of Natural Sciences (NINS) (grant Nos. AB022006, AB031010, AB031014). This work is partly financed by the Spanish Ministry of Economics and Competitiveness through grant No. PGC2018-098153-B-C31. V.K. gratefully acknowledges support from NASA via grant No. NNX17AF81G. M.L. acknowledges support from the Swiss National Science Foundation under grant No. PCEFP2_194576. The contribution of M.L. has been carried out within the framework of the NCCR PlanetS supported by the Swiss National Science Foundation. C.I.C. acknowledges support by NASA Headquarters under the NASA Earth and Space Science Fellowship Program through grant No. 80NSSC18K1114. NEID is funded by NASA/JPL under contract 1547612. We acknowledge support from NSF grant Nos. AST-190950 and 1910954.

We present the discovery and validation of a temperate sub-Neptune around the nearby mid-M dwarf TIC 470381900 (TOI-1696), with a radius of $3.09 \pm 0.11 \,R_\oplus$ and an orbital period of $2.5 \,\rm{days}$, using a combination of TESS and follow-up observations using ground-based telescopes. Joint analysis of multi-band photometry from TESS, MuSCAT, MuSCAT3, Sinistro, and KeplerCam confirmed the transit signal to be achromatic as well as refined the orbital ephemeris. High-resolution imaging with Gemini/'Alopeke and high-resolution spectroscopy with the Subaru/IRD confirmed that there are no stellar companions or background sources to the star. The spectroscopic observations with IRD and IRTF/SpeX were used to determine the stellar parameters, and found the host star is an M4 dwarf with an effective temperature of $T_{eff} = 3185 \pm 76\,\rm{K}$ and a metallicity of [Fe/H] $=0.336 \pm 0.060 \,\rm{dex}$. The radial velocities measured from IRD set a $2$-$\sigma$ upper limit on the planetary mass to be $48.8 \,M_\oplus$. The large radius ratio ($R_p/R_\star \sim 0.1$) and the relatively bright NIR magnitude ($J=12.2 \,\rm{mag}$) make this planet an attractive target for further followup observations. TOI-1696b is one of the planets belonging to the Neptunian desert with the highest transmission spectroscopy metric discovered to date, making it an interesting candidate for atmospheric characterizations with JWST., Comment: 25 pages, 18 figures, 3 tables, Submitted to AJ

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 lis of authors: Fukui, Akihiko; Kimura, Tadahiro; Hirano, Teruyuki; Narita, Norio; Kodama, Takanori; Hori, Yasunori; Ikoma, Masahiro; Palle, Enric; Murgas, Felipe; Parviainen, Hannu; Kawauchi, Kiyoe; Mori, Mayuko; Esparza-Borges, Emma; Bieryla, Allyson; Irwin, Jonathan; Safonov, Boris S.; Stassun, Keivan G.; Alvarez-Hernandez, Leticia; Bejar, Victor J. S.; Casasayas-Barris, Nuria; Chen, Guo; Crouzet, Nicolas; de Leon, Jerome P.; Isogai, Keisuke; Kagetani, Taiki; Klagyivik, Peter; Korth, Judith; Kurita, Seiya; Kusakabe, Nobuhiko; Livingston, John; Luque, Rafael; Madrigal-Aguado, Alberto; Morello, Giuseppe; Nishiumi, Taku; Orell-Miquel, Jaume; Oshagh, Mahmoudreza; Sanchez-Benavente, Manuel; Stangret, Monika; Terada, Yuka; Watanabe, Noriharu; Zou, Yujie; Tamura, Motohide; Kurokawa, Takashi; Kuzuhara, Masayuki; Nishikawa, Jun; Omiya, Masashi; Vievard, Sebastien; Ueda, Akitoshi; Latham, David W.; Quinn, Samuel N.; Strakhov, Ivan S.; Belinski, Alexandr A.; Jenkins, Jon M.; Ricker, George R.; Seager, Sara; Vanderspek, Roland; Winn, Joshua N.; Charbonneau, David; Ciardi, David R.; Collins, Karen A.; Doty, John P.; Bachelet, Etienne; Harbeck, Daniel., We report the discovery of TOI-2285b, a sub-Neptune-sized planet transiting a nearby (42 pc) M dwarf with a period of 27.3 d. We identified the transit signal from the Transiting Exoplanet Survey Satellite photometric data, which we confirmed with ground-based photometric observations using the multiband imagers MuSCAT2 and MuSCAT3. Combining these data with other follow-up observations including high-resolution spectroscopy with the Tillinghast Reflector Echelle Spectrograph, high-resolution imaging with the SPeckle Polarimeter, and radial velocity (RV) measurements with the InfraRed Doppler instrument, we find that the planet has a radius of 1.74±0.08R⊕⁠, a mass of, Funding for the TESS mission is provided by NASA’s Science Mission Directorate. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS SPOC. 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. This paper includes data that are publicly available from the MAST. 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 NASA under the Exoplanet Exploration Program. This work makes use of observations from the LCO global telescope network. This paper is based on observations made with the MuSCAT3 instrument, developed by the Astrobiology Center (ABC) and under financial supports by JSPS KAKENHI (JP18H05439) and JST PRESTO (JPMJPR1775), at FTN on Maui, HI, operated by the LCO, and observations made with the MuSCAT2 instrument, developed by ABC, at TCS operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This paper is partially based on observations made at the CMO SAI MSU with the support by M.V. Lomonosov Moscow State University Program of Development. This work is partly supported by JSPS KAKENHI Grant Numbers 22000005, JP15H02063, JP17H04574, JP18H05439, JP18H05442, JP20K14518, Grant-in-Aid for JSPS Fellows Grant Number JP20J21872, JST PRESTO Grant Number JPMJPR1775, and the ABC of National Institutes of Natural Sciences (Grant Number AB031010). This work is partly financed by the Spanish Ministry of Economics and Competitiveness through grants PGC2018-098153-B-C31 and PID2019-109522GB-C53. A.A.B., B.S.S., and I.A.S. acknowledge the support of Ministry of Science and Higher Education of the Russian Federation under the grant 075-15-2020-780 (N13.1902.21.0039). N.C.B. and G.M. acknowledge the funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program under grant agreement No. 694513 and under the Marie Skłodowska-Curie grant agreement No. 895525, respectively. J.K. acknowledges the support of the Swedish National Space Agency (SNSA; DNR 2020-00104). R.L. acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación, through project PID2019-109522GB-C52/AEI/10.13039/501100011033, and the Centre of Excellence “Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709).

Exploring the properties of exoplanets near or inside the radius valley provides insights on the transition from the rocky super-Earths to the larger, hydrogen-rich atmosphere mini-Neptunes. Here, we report the discovery of TOI-1452 b, a transiting super-Earth ($R_{\rm p} = 1.67 \pm 0.07$ R$_{\oplus}$) in an 11.1--day temperate orbit ($T_{\rm eq} = 326 \pm 7$ K) around the primary member ($H = 10.0$, $T_{\rm eff} = 3185 \pm 50$ K) of a nearby visual binary M dwarf. The transits were first detected by TESS, then successfully isolated between the two $3.2^{\prime\prime}$ companions with ground-based photometry from OMM and MuSCAT3. The planetary nature of TOI-1452 b was established through high-precision velocimetry with the near-infrared SPIRou spectropolarimeter as part of the ongoing SPIRou Legacy Survey. The measured planetary mass ($4.8 \pm 1.3$ M$_{\oplus}$) and inferred bulk density ($5.6^{+1.8}_{-1.6}$ g/cm$^3$) is suggestive of a rocky core surrounded by a volatile-rich envelope. More quantitatively, the mass and radius of TOI-1452 b, combined with the stellar abundance of refractory elements (Fe, Mg and Si) measured by SPIRou, is consistent with a core mass fraction of $18\pm6$ % and a water mass fraction of $22^{+21}_{-13}$%. The water world candidate TOI-1452 b is a prime target for future atmospheric characterization with JWST, featuring a Transmission Spectroscopy Metric similar to other well-known temperate small planets such as LHS 1140 b and K2-18 b. The system is located near Webb's northern Continuous Viewing Zone, implying that is can be followed at almost any moment of the year., Published in The Astronomical Journal

We report the discovery of an eccentric hot Neptune and a non-transiting outer planet around TOI-1272. We identified the eccentricity of the inner planet, with an orbital period of 3.3 d and $R_{\rm p,b} = 4.1 \pm 0.2$ $R_\oplus$, based on a mismatch between the observed transit duration and the expected duration for a circular orbit. Using ground-based radial velocity measurements from the HIRES instrument at the Keck Observatory, we measured the mass of TOI-1272b to be $M_{\rm p,b} = 25 \pm 2$ $M_\oplus$. We also confirmed a high eccentricity of $e_b = 0.34 \pm 0.06$, placing TOI-1272b among the most eccentric well-characterized sub-Jovians. We used these RV measurements to also identify a non-transiting outer companion on an 8.7-d orbit with a similar mass of $M_{\rm p,c}$ sin$i= 27 \pm 3$ $M_\oplus$ and $e_c \lesssim 0.35$. Dynamically stable planet-planet interactions have likely allowed TOI-1272b to avoid tidal eccentricity decay despite the short circularization timescale expected for a close-in eccentric Neptune. TOI-1272b also maintains an envelope mass fraction of $f_{\rm env} \approx 11\%$ despite its high equilibrium temperature, implying that it may currently be undergoing photoevaporation. This planet joins a small population of short-period Neptune-like planets within the "Hot Neptune Desert" with a poorly understood formation pathway., Comment: Accepted at The Astronomical Journal; 17 pages, 11 figures

We report the near-infrared radial-velocity (RV) discovery of a super-Earth planet on a 10.77-day orbit around the M4.5 dwarf Ross 508 ($J_\mathrm{mag}=9.1$). Using precision RVs from the Subaru Telescope IRD (InfraRed Doppler) instrument, we derive a semi-amplitude of $3.92^{+0.60}_{-0.58}$ ${\rm m\,s}^{-1}$, corresponding to a planet with a minimum mass $m \sin i = 4.00^{+0.53}_{-0.55}\ M_{\oplus}$. We find no evidence of significant signals at the detected period in spectroscopic stellar activity indicators or MEarth photometry. The planet, Ross 508 b, has a semimajor-axis of $0.05366^{+0.00056}_{-0.00049}$ au. This gives an orbit-averaged insolation of $\approx$1.4 times the Earth's value, placing Ross 508 b near the inner edge of its star's habitable zone. We have explored the possibility that the planet has a high eccentricity and its host is accompanied by an additional unconfirmed companion on a wide orbit. Our discovery demonstrates that the near-infrared RV search can play a crucial role to find a low-mass planet around cool M dwarfs like Ross 508., Comment: Accepted for publication in PASJ (May 23, 2022)

Full list of authors: Hatzes, Artie P.; Gandolfi, Davide; Korth, Judith; Rodler, Florian; Sabotta, Silvia; Esposito, Massimiliano; Barragán, Oscar; Van Eylen, Vincent; Livingston, John H.; Serrano, Luisa Maria; Luque, Rafael; Smith, Alexis M. S.; Redfield, Seth; Persson, Carina M.; Pätzold, Martin; Palle, Enric; Nowak, Grzegorz; Osborne, Hannah L. M.; Narita, Norio; Mathur, Savita; Lam, Kristine W. F.; Kabáth, Petr; Johnson, Marshall C.; Guenther, Eike W.; Grziwa, Sascha; Goffo, Elisa; Fridlund, Malcolm; Endl, Michael; Deeg, Hans J.; Csizmadia, Szilard; Cochran, William D.; Cuesta, Lucía González; Chaturvedi, Priyanka; Carleo, Ilaria; Cabrera, Juan; Beck, Paul G.; Albrecht, Simon.--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., π Men hosts a transiting planet detected by the Transiting Exoplanet Survey Satellite space mission and an outer planet in a 5.7 yr orbit discovered by radial velocity (RV) surveys. We studied this system using new RV measurements taken with the HARPS spectrograph on ESO's 3.6 m telescope, as well as archival data. We constrain the stellar RV semiamplitude due to the transiting planet, π Men c, as Kc = 1.21 ± 0.12 m s−1, resulting in a planet mass of Mc = 3.63 ± 0.38 M⊕. A planet radius of Rc = 2.145 ± 0.015 R⊕ yields a bulk density of ρc = 2.03 ± 0.22 g cm−3. The precisely determined density of this planet and the brightness of the host star make π Men c an excellent laboratory for internal structure and atmospheric characterization studies. Our HARPS RV measurements also reveal compelling evidence for a third body, π Men d, with a minimum mass Md sin id = 13.38 ± 1.35 M⊕ orbiting with a period of Porb,d = 125 days on an eccentric orbit (ed = 0.22). A simple dynamical analysis indicates that the orbit of π Men d is stable on timescales of at least 20 Myr. Given the mutual inclination between the outer gaseous giant and the inner rocky planet and the presence of a third body at 125 days, π Men is an important planetary system for dynamical and formation studies. © 2022. The Author(s). Published by the American Astronomical Society., This work was supported by the KESPRINT collaboration, an international consortium devoted to the characterization and research of exoplanets discovered with space-based missions (www.kesprint.science). S.G., M.P., S.C., A.P.H., K.W.F.L., M.E., and H.R. acknowledge support by DFG grants PA525/18-1, PA525/19-1, PA525/20-1, HA 3279/12-1, and RA 714/14-1 within the DFG Schwerpunkt SPP 1992, "Exploring the Diversity of Extrasolar Planets." L.M.S. and D.G. gratefully acknowledge financial support from the CRT foundation under grant No. 2018.2323 "Gaseous or rocky? Unveiling the nature of small worlds." J.K. gratefully acknowledges the support of the Swedish National Space Agency (SNSA; DNR 2020-00104). P.G.B. acknowledges the financial support by NAWI Graz. We thank Matthias Hoeft and Alexander Drabent for use of the computer of the Tautenburg radio group for our dynamical study., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

The James Webb Space Telescope will be able to probe the atmospheres and surface properties of hot, terrestrial planets via emission spectroscopy. We identify 18 potentially terrestrial planet candidates detected by the Transiting Exoplanet Survey Satellite (TESS) that would make ideal targets for these observations. These planet candidates cover a broad range of planet radii (R p ∼ 0.6–2.0R ⊕) and orbit stars of various magnitudes (K s = 5.78–10.78, V = 8.4–15.69) and effective temperatures (T eff ∼ 3000–6000 K). We use ground-based observations collected through the TESS Follow-up Observing Program (TFOP) and two vetting tools—DAVE and TRICERATOPS—to assess the reliabilities of these candidates as planets. We validate 13 planets: TOI-206 b, TOI-500 b, TOI-544 b, TOI-833 b, TOI-1075 b, TOI-1411 b, TOI-1442 b, TOI-1693 b, TOI-1860 b, TOI-2260 b, TOI-2411 b, TOI-2427 b, and TOI-2445 b. Seven of these planets (TOI-206 b, TOI-500 b, TOI-1075 b, TOI-1442 b, TOI-2260 b, TOI-2411 b, and TOI-2445 b) are ultra-short-period planets. TOI-1860 is the youngest (133 ± 26 Myr) solar twin with a known planet to date. TOI-2260 is a young (321 ± 96 Myr) G dwarf that is among the most metal-rich ([Fe/H] = 0.22 ± 0.06 dex) stars to host an ultra-short-period planet. With an estimated equilibrium temperature of ∼2600 K, TOI-2260 b is also the fourth hottest known planet with R p < 2 R ⊕.

WASP-33b, a hot Jupiter around a hot star, is a rare system in which nodal precession has been discovered. We updated the model for the nodal precession of WASP-33b by adding new observational points. Consequently, we found a motion of the nodal precession spanning 11 yr. We present homogenous Doppler tomographic analyses of eight data sets, including two new data sets from TS23 and HIDES, obtained between 2008 and 2019, to illustrate the variations in the projected spin–orbit obliquity of WASP-33b and its impact parameter. We also present its impact parameters based on photometric transit observations captured by MuSCAT in 2017 and MuSCAT2 in 2018. We derived its real spin–orbit obliquity ψ, stellar spin inclination is, and stellar gravitational quadrupole moment J2 from the time variation models of the two orbital parameters. We obtained $\psi = 108.19^{+0.95}_{-0.97}$ deg, $i_\mathit{ s} = 58.3^{+4.6}_{-4.2}$ deg, and $J_2=(1.36^{+0.15}_{-0.12}) \times 10^{-4}$. Our J2 value was slightly smaller than the theoretically predicted value, which may indicate that its actual stellar internal structure is different from the theoretical one. We derived the nodal precession speed $\dot{\theta }=0.507^{+0.025}_{-0.022}$ deg yr−1, and its period $P_{\mathrm{pre}}=709^{+33}_{-34}$ yr, and found that WASP-33b transits in front of WASP-33 for only ∼ 20 per cent of the entire nodal precession period.

TOI-640 b is a hot, puffy Jupiter with a mass of 0.57 ± 0.02 MJ and radius of 1.72 ± 0.05 RJ, orbiting a slightly evolved F-type star with a separation of 6.33−0.06+0.07 R⋆. Through spectroscopic in-transit observations made with the HARPS spectrograph, we measured the Rossiter-McLaughlin effect, analysing both in-transit radial velocities and the distortion of the stellar spectral lines. From these observations, we find the host star to have a projected obliquity of λ = 184 ± 3°. From the TESS light curve, we measured the stellar rotation period, allowing us to determine the stellar inclination, i⋆ = 23−2+3°, meaning we are viewing the star pole-on. Combining this with the orbital inclination allowed us to calculate the host star obliquity, ψ = 104 ± 2°. TOI-640 b joins a group of planets orbiting over stellar poles within the range 80°–125°. The origin of this orbital configuration is not well understood.

Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution., Comment: Ariel Definition Study Report, 147 pages. Reviewed by ESA Science Advisory Structure in November 2020. Original document available at: https://www.cosmos.esa.int/documents/1783156/3267291/Ariel_RedBook_Nov2020.pdf/

Alkali metal lines are one of the most important key opacity sources for understanding exoplanetary atmospheres because the Na I resonance doublets are thought to be the cause of low albedo, as the alkali metal's wide line wings absorb almost all of the incoming stellar irradiation. High-resolution transmission spectroscopy of Na absorption lines can be used to investigate the temperature of the thermosphere of hot Jupiters, which is increased by stellar X-ray and EUV irradiation. We applied high-resolution transmission spectroscopy to the ultra-hot Jupiter WASP-76 b with the High Dispersion Spectrograph (HDS) on the Subaru 8.2 m telescope. We report the detection of strong Na D excess absorption with line contrasts of 0.42 $\pm$ 0.03 % (D1 at 5895.92 \r{A}) and 0.38 $\pm$ 0.04 % (D2 at 5889.95 \r{A}), FWHMs of 1.63 $\pm$ 0.13 \r{A} (D1) and 1.87 $\pm$ 0.22 \r{A} (D2), and EWs of (7.29 $\pm$ 1.43) $\times$ 10$^{-3}$ \r{A} (D1) and (7.56 $\pm$ 2.38) $\times$ 10$^{-3}$ \r{A} (D2). These results show that the Na D absorption lines are shallower and broader than those in previous work, whereas the absorption signals over the same passband are consistent with those in previous work. We derive the best-fitted isothermal temperature of 3700 K (without rotation) and 4200 K (with rotation). These results suggest the possibility of the existence of a thermosphere because the derived atmospheric temperature is higher than the equilibrium temperature ($\sim$ 2160 K)., Comment: 23 pages, 13 figures, accepted for publication in PASJ

Ultra-short-period (USP) exoplanets have orbital periods shorter than one day. Precise masses and radii of USPs could provide constraints on their unknown formation and evolution processes. We report the detection and characterization of the USP planet GJ 367b using high precision photometry and radial velocity observations. GJ 367b orbits a bright (V-band magnitude = 10.2), nearby, red (M-type) dwarf star every 7.7 hours. GJ 367b has a radius of $0.718 \pm 0.054$ Earth-radii, a mass of $0.546 \pm 0.078$ Earth-masses, making it a sub-Earth. The corresponding bulk density is $8.106 \pm 2.165$ g cm$^-3$, close to that of iron. An interior structure model predicts the planet has an iron core radius fraction of $86 \pm 5\%$, similar to Mercury's interior., Comment: Note: "This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science , (2021-12-03), doi: 10.1126/science.aay3253"

We report on precise Doppler measurements of L231-32 (TOI-270), a nearby M dwarf ($d=22$ pc, $M_\star = 0.39$ M$_\odot$, $R_\star = 0.38$ R$_\odot$), which hosts three transiting planets that were recently discovered using data from the Transiting Exoplanet Survey Satellite (TESS). The three planets are 1.2, 2.4, and 2.1 times the size of Earth and have orbital periods of 3.4, 5.7, and 11.4 days. We obtained 29 high-resolution optical spectra with the newly commissioned Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations (ESPRESSO) and 58 spectra using the High Accuracy Radial velocity Planet Searcher (HARPS). From these observations, we find the masses of the planets to be $1.58 \pm 0.26$, $6.15 \pm 0.37$, and $4.78 \pm 0.43$ M$_\oplus$, respectively. The combination of radius and mass measurements suggests that the innermost planet has a rocky composition similar to that of Earth, while the outer two planets have lower densities. Thus, the inner planet and the outer planets are on opposite sides of the `radius valley' -- a region in the radius-period diagram with relatively few members, which has been interpreted as a consequence of atmospheric photo-evaporation. We place these findings into the context of other small close-in planets orbiting M dwarf stars, and use support vector machines to determine the location and slope of the M dwarf ($T_\mathrm{eff} < 4000$ K) radius valley as a function of orbital period. We compare the location of the M dwarf radius valley to the radius valley observed for FGK stars, and find that its location is a good match to photo-evaporation and core-powered mass loss models. Finally, we show that planets below the M dwarf radius valley have compositions consistent with stripped rocky cores, whereas most planets above have a lower density consistent with the presence of a H-He atmosphere., Accepted for publication in MNRAS

The public, all-sky surveys Gaia and TESS provide the ability to identify new young associations and determine their ages. These associations enable study of planetary evolution by providing new opportunities to discover young exoplanets. A young association was recently identified by Tang et al. and F{\"u}rnkranz et al. using astrometry from Gaia (called "Group-X" by the former). In this work, we investigate the age and membership of this association; and we validate the exoplanet TOI 2048 b, which was identified to transit a young, late G dwarf in Group-X using photometry from TESS. We first identified new candidate members of Group-X using Gaia EDR3 data. To infer the age of the association, we measured rotation periods for candidate members using TESS data. The clear color--period sequence indicates that the association is the same age as the $300\pm50$ Myr-old NGC 3532. We obtained optical spectra for candidate members that show lithium absorption consistent with this young age. Further, we serendipitously identify a new, small association nearby Group-X, which we call MELANGE-2. Lastly, we statistically validate TOI 2048 b, which is $2.6\pm0.2$ \rearth\ radius planet on a 13.8-day orbit around its 300 Myr-old host star., Comment: Revised to correct error in reported planet radius (original: 2.1 Earth radii, corrected: 2.6 Earth radii) and units for planetary radius ratio entries in Table 8. All data tables available open-access with the AJ article

Full list of authors: Bluhm, P.; Pallé, E.; Molaverdikhani, K.; Kemmer, J.; Hatzes, A. P.; Kossakowski, D.; Stock, S.; Caballero, J. A.; Lillo-Box, J.; Béjar, V. J. S.; Soto, M. G.; Amado, P. J.; Brown, P.; Cadieux, C.; Cloutier, R.; Collins, K. A.; Collins, K. I.; Cortés-Contreras, M.; Doyon, R.; Dreizler, S.; Espinoza, N.; Fukui, A.; González-Álvarez, E.; Henning, Th.; Horne, K.; Jeffers, S. V.; Jenkins, J. M.; Jensen, E. L. N.; Kaminski, A.; Kielkopf, J. F.; Kusakabe, N.; Kürster, M.; Lafrenière, D.; Luque, R.; Murgas, F.; Montes, D.; Morales, J. C.; Narita, N.; Passegger, V. M.; Quirrenbach, A.; Schöfer, P.; Reffert, S.; Reiners, A.; Ribas, I.; Ricker, G. R.; Seager, S.; Schweitzer, A.; Schwarz, R. P.; Tamura, M.; Trifonov, T.; Vanderspek, R.; Winn, J.; Zechmeister, M.; Zapatero Osorio, M. R., Dynamical histories of planetary systems, as well as the atmospheric evolution of highly irradiated planets, can be studied by characterizing the ultra-short-period planet population, which the TESS mission is particularly well suited to discover. Here, we report on the follow-up of a transit signal detected in the TESS sector 19 photometric time series of the M3.0 V star TOI-1685 (2MASS J04342248+4302148). We confirm the planetary nature of the transit signal, which has a period of Pb = 0.6691403-0.0000021+0.0000023 d, using precise radial velocity measurements taken with the CARMENES spectrograph. From the joint photometry and radial velocity analysis, we estimate the following parameters for TOI-1685 b: a mass of Mb = 3.78-0.63+0.63 M? , a radius of Rb = 1.70-0.07+0.07 R? , which together result in a bulk density of ρb = 4.21-0.82+0.95 g cm-3, and an equilibrium temperature of Teq = 1069-16+16 K. TOI-1685 b is the least dense ultra-short-period planet around an M dwarf known to date. TOI-1685 b is also one of the hottest transiting super-Earth planets with accurate dynamical mass measurements, which makes it a particularly attractive target for thermal emission spectroscopy. Additionally, we report with moderate evidence an additional non-transiting planet candidate in the system, TOI-1685 [c], which has an orbital period of Pc = 9.02-0.12+0.10 d. © ESO 2021., 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 Ciències de l’Espai, Institut für Astrophysik Göttingen, Universidad Complutense de Madrid, Thüringer Landessternwarte Tautenburg, Instituto de Astrofísica de Canarias, Hamburger Sternwarte, Cen tro 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. 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]/AEI/10.13039/501100011033, PGC2018-098153-B-C33, and the Centre of Excellence “Severo Ochoa” and “María de Maeztu” awards to the Instituto de Astrofísica de Canarias (SEV-2015-0548), Instituto de Astrofísica de Andalucía (SEV-2017-0709), and Centro de Astro biología (MDM-2017-0737), the Generalitat de Catalunya/CERCA programme,“la Caixa” Foundation (100010434), European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agree ment No. 847 648 (LCF/BQ/PI20/11760023), a University Research Support Grant from the National Astronomical Observatory of Japan, JSPS KAKENHI (JP15H02063, JP18H01265, JP18H05439, JP18H05442, and JP22000005), JST PRESTO (JPMJPR1775), UK Science and Technology Facilities Council (ST/R000824/1), and NASA (NNX17AG24G) This article is based on obser vations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos Sánchez operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide, with the Observatoire du Mont-Mégantic, financed by Université de Montréal, Université Laval, the National Sciences and Engineer ing Council of Canada, the Fonds québécois de la recherche sur la Nature et les technologies, and the Canada Economic Development program, and with the LCOGT network. LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program , which is funded by NSF. Funding for the TESS mission is provided by NASA’s Science Mission Directorate. We acknowledge the use of public TESS 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 Aeronau tics and Space Administration under the Exoplanet Exploration Program. This research also made use of AstroImageJ, and TAPIR, and the SIMBAD database, operated at CDS, Strasbourg, France.

The TESS mission has reported a wealth of new planetary systems around bright and nearby stars amenable for detailed characterization of the planet properties and their atmospheres. However, not all interesting TESS planets orbit around bright host stars. TOI-263b is a validated ultra-short period substellar object in a 0.56-day orbit around a faint (V=18.97) M3.5 dwarf star. The substellar nature of TOI-263b was explored using multi-color photometry, which determined a true radius of 0.87+-0.21 Rj, establishing TOI-263b's nature ranging from an inflated Neptune to a brown dwarf. The orbital period-radius parameter space occupied by TOI-263b is quite unique, which prompted a further characterization of its true nature. Here, we report radial velocity measurements of TOI-263 obtained with 3 VLT units and the ESPRESSO spectrograph to retrieve the mass of TOI-263b. We find that TOI-263b is a brown dwarf with a mass of 61.6+-4.0 Mj. Additionally, the orbital period of the brown dwarf is found to be synchronized with the rotation period of the host star, and the system is found to be relatively active, possibly revealing a star--brown dwarf interaction. All these findings suggest that the system's formation history might be explained via disc fragmentation and later migration to close-in orbits. If the system is found to be unstable, TOI-263 is an excellent target to test the migration mechanisms before the brown dwarf becomes engulfed by its parent star., Accepted for Publication in Astronomy and Astrophysics

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. © 2021 American Association for the Advancement of Science. All rights reserved., Funding was provided by Deutsche Forschungsgemeinschaft through research unit FOR2544 "Blue Planets around Red Stars" and priority program SPP1992 "Exploring the Diversity of Extrasolar Planets"; Agencia Estatal de Investigacion of the Ministerio de Ciencia e Innovacion and the European Regional Development Fund through projects PID2019-109522GB-C51/2/3/4, PGC2018-098153-B-C33, SEV-2017-0709, MDM-2017-0737, AYA2016-79425-C3-1/2/3-P, ESP2016-80435-C2-1-R, and SEV-2015-0548; Klaus Tschira Stiftung; European Union's Horizon 2020 through Marie Sklodowska Curie grant 713673; "la Caixa" through INPhINT grant LCF/BQ/IN17/1162033; NASA through grants NNX17AG24G, 80NSSC19K0533, 80NSSC19K1721, and 80NSSC18K158 and the NASA Science Mission Directorate; Japan Society for the Promotion of Science KAKENHI through grants JP17H04574, JP18H01265, and JP18H05439; and Japan Science and Technology Agency PRESTO through grant JPMJPR1775.

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

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

We report the discovery of an ultrahot Jupiter with an extremely short orbital period of $0.67247414\,\pm\,0.00000028$ days ($\sim$16 hr). The $1.347 \pm 0.047$ $R_{\rm Jup}$ planet, initially identified by the Transiting Exoplanet Survey Satellite (TESS) mission, orbits TOI-2109 (TIC 392476080): a $T_{\rm eff} \sim 6500$ K F-type star with a mass of $1.447 \pm 0.077$ $M_{\rm Sun}$, a radius of $1.698 \pm 0.060$ $R_{\rm Sun}$, and a rotational velocity of $v\sin i_* = 81.9 \pm 1.7$ km s$^{-1}$. The planetary nature of TOI-2109b was confirmed through radial velocity measurements, which yielded a planet mass of $5.02 \pm 0.75$ $M_{\rm Jup}$. Analysis of the Doppler shadow in spectroscopic transit observations indicates a well-aligned system, with a sky-projected obliquity of $\lambda = 1\overset{\circ}{.}7 \pm 1\overset{\circ}{.}7$. From the TESS full-orbit light curve, we measured a secondary eclipse depth of $731 \pm 46$ ppm, as well as phase-curve variations from the planet's longitudinal brightness modulation and ellipsoidal distortion of the host star. Combining the TESS-band occultation measurement with a $K_s$-band secondary eclipse depth ($2012 \pm 80$ ppm) derived from ground-based observations, we find that the dayside emission of TOI-2109b is consistent with a brightness temperature of $3631 \pm 69$ K, making it the second hottest exoplanet hitherto discovered. By virtue of its extreme irradiation and strong planet-star gravitational interaction, TOI-2109b is an exceptionally promising target for intensive follow-up studies using current and near-future telescope facilities to probe for orbital decay, detect tidally driven atmospheric escape, and assess the impacts of H$_2$ dissociation and recombination on the global heat transport., Comment: 30 pages, 17 figures, published in AJ

We present the discovery of a highly irradiated and moderately inflated ultra-hot Jupiter, TOI-1431b/MASCARA-5b (HD 201033b), first detected by NASA's Transiting Exoplanet Survey Satellite mission (TESS) and the Multi-site All-Sky CAmeRA (MASCARA). The signal was established to be of planetary origin through radial velocity measurements obtained using SONG, SOPHIE, FIES, NRES, and EXPRES, which show a reflex motion of $K=294.1\pm1.1$ m s$^{-1}$. A joint analysis of the TESS and ground-based photometry and radial velocity measurements reveals that TOI-1431b has a mass of $M_{p}=3.12\pm0.18$ $\rm{M_J}$ ($990\pm60$ M$_{\oplus}$), an inflated radius of $R_{p}=1.49\pm0.05$ $\rm{R_J}$ ($16.7\pm0.6$ R$_{\oplus}$), and an orbital period of $P=2.650237\pm0.000003$ d. Analysis of the spectral energy distribution of the host star reveals that the planet orbits a bright ($\mathrm{V}=8.049$ mag) and young ($0.29^{+0.32}_{-0.19}$ Gyr) Am type star with $T_{\rm eff}=7690^{+400}_{-250}$ $\rm{K}$, resulting in a highly irradiated planet with an incident flux of $\langle F \rangle=7.24^{+0.68}_{-0.64}\times$10$^9$ erg s$^{-1}$ cm$^{-2}$ ($5300^{+500}_{-470}\mathrm{S_{\oplus}}$) and an equilibrium temperature of $T_{eq}=2370\pm70$ K. TESS photometry also reveals a secondary eclipse with a depth of $127^{+4}_{-5}$ppm as well as the full phase curve of the planet's thermal emission in the red-optical. This has allowed us to measure the dayside and nightside temperature of its atmosphere as $T_\mathrm{day}=3004\pm64$ K and $T_\mathrm{night}=2583\pm63$ K, the second hottest measured nightside temperature. The planet's low day/night temperature contrast ($\sim$420 K) suggests very efficient heat transport between the dayside and nightside hemispheres., Accepted for publication in the Astronomical Journal. 39 pages, 18 figures, and 4 tables

Detailed chemical analyses of M dwarfs are scarce but necessary to constrain the formation environment and internal structure of planets being found around them. We present elemental abundances of 13 M dwarfs (2900 < Teff < 3500 K) observed in the Subaru/IRD planet search project. They are mid-to-late M dwarfs whose abundance of individual elements has not been well studied. We use the high-resolution (~70,000) near-infrared (970-1750 nm) spectra to measure the abundances of Na, Mg, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Sr by the line-by-line analysis based on model atmospheres, with typical errors ranging from 0.2 dex for [Fe/H] to 0.3-0.4 dex for other [X/H]. We measure radial velocities from the spectra and combine them with Gaia astrometry to calculate the Galactocentric space velocities UVW. The resulting [Fe/H] values agree with previous estimates based on medium-resolution K-band spectroscopy, showing a wide distribution of metallicity (-0.6 < [Fe/H] < +0.4). The abundance ratios of individual elements [X/Fe] are generally aligned with the solar values in all targets. While the [X/Fe] distributions are comparable to those of nearby FGK stars, most of which belong to the thin disk population, the most metal-poor object, GJ 699, could be a thick disk star. The UVW velocities also support this. The results raise the prospect that near-infrared spectra of M dwarfs obtained in the planet search projects can be used to grasp the trend of elemental abundances and Galactic stellar population of nearby M dwarfs., 31 pages, 16 figures, accepted for publication in AJ

We report the discovery of two short-period Saturn-mass planets, one transiting the G subgiant TOI-954 (TIC 44792534, $ V = 10.343 $, $ T = 9.78 $) observed in TESS sectors 4 and 5, and one transiting the G dwarf K2-329 (EPIC 246193072, $ V = 12.70 $, $ K = 10.67 $) observed in K2 campaigns 12 and 19. We confirm and characterize these two planets with a variety of ground-based archival and follow-up observations, including photometry, reconnaissance spectroscopy, precise radial velocity, and high-resolution imaging. Combining all available data, we find that TOI-954 b has a radius of $0.852_{-0.062}^{+0.053} \, R_{\mathrm{J}}$ and a mass of $0.174_{-0.017}^{+0.018} \, M_{\mathrm{J}}$ and is in a 3.68 day orbit, while K2-329 b has a radius of $0.774_{-0.024}^{+0.026} \, R_{\mathrm{J}}$ and a mass of $0.260_{-0.022}^{+0.020} \, M_{\mathrm{J}}$ and is in a 12.46 day orbit. As TOI-954 b is 30 times more irradiated than K2-329 b but more or less the same size, these two planets provide an opportunity to test whether irradiation leads to inflation of Saturn-mass planets and contribute to future comparative studies that explore Saturn-mass planets at contrasting points in their lifetimes., Comment: 28 pages, 9 figures, 11 tables, accepted by AJ, ancillary data also available at https://github.com/vulpicastor/toi954-data

Context: We report the discovery of TOI-519 b (TIC 218795833), a transiting substellar object (R = 1.07 RJup) orbiting a faint M dwarf (V = 17.35) on a 1.26 d orbit. Brown dwarfs and massive planets orbiting M dwarfs on short-period orbits are rare, but more have already been discovered than expected from planet formation models. TOI-519 is a valuable addition into this group of unlikely systems, and adds towards our understanding of the boundaries of planet formation. Aims: We set out to determine the nature of the Transiting Exoplanet Survey Satellite (TESS ) object of interest TOI-519 b. Methods: Our analysis uses a SPOC-pipeline TESS light curve from Sector 7, multicolour transit photometry observed with MuSCAT2 and MuSCAT, and transit photometry observed with the LCOGT telescopes. We estimate the radius of the transiting object using multicolour transit modelling, and set upper limits for its mass, effective temperature, and Bond albedo using a phase curve model that includes Doppler boosting, ellipsoidal variations, thermal emission, and reflected light components. Results: TOI-519 b is a substellar object with a radius posterior median of 1.07 RJup and 5th and 95th percentiles of 0.66 and 1.20 RJup, respectively, where most of the uncertainty comes from the uncertainty in the stellar radius. The phase curve analysis sets an upper effective temperature limit of 1800 K, an upper Bond albedo limit of 0.49, and a companion mass upper limit of 14 MJup. The companion radius estimate combined with the Teff and mass limits suggests that the companion is more likely a planet than a brown dwarf, but a brown-dwarf scenario is more likely a priori given the lack of known massive planets in 1 day orbits around M dwarfs with Teff < 3800 K, and the existence of some (but few) brown dwarfs., Accepted to A&A

We thank Dr. S. Hoyer from the Laboratoire d'Astrophysique de Marseille (LAM) in France for the helpful discussions. We also thank the anonymous reviewer for the helpful comments and suggestions. This work was supported by the Erasmus+ grant number 2017-1-CZ01-KA203-035562, by the VEGA grant of the Slovak Academy of Sciences number 2/0031/18, by an ESA PRODEX grant under contracting with the ELTE University, by the GINOP number 2.3.2-15-2016-00003 of the Hungarian National Research, Development and Innovation Office, and by the City of Szombathely under agreement number 67.177-21/2016. This paper includes data collected with the TESS mission, obtained from the MAST data archive at the Space Telescope Science Institute (STScI). Funding for the TESS mission is provided by the NASA Explorer Program. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This article is based on observations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos Sanchez operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This work was partly financed by the Spanish Ministry of Economics and Competitiveness through grant number PGC2018098153-B-C31. This work was partly supported by JSPS KAKENHI grant numbers JP17H04574, JP18H01265 and JP18H05439, and JST PRESTO grant number JPMJPR1775. This work was partly supported by Grant-in-Aid for JSPS Fellows, grant number JP20J21872. TP acknowledges support from the Slovak Research and Development Agency - the contract No. APVV-20-0148. MT was supported by MEXT/JSPS KAKENHI grant numbers 18H05442, 15H02063, and 22000005. AC acknowledges financial support from the State Agency for Research of the Spanish MCIU through the `Center of Excellence Severo Ochoa' award for the Instituto de Astrophysics of Andalusia (SEV-2017-0709). We acknowledge funding from the European Research Council under the European Union's Horizon 2020 research and innovation program under grant agreement number 694513., Up to now, WASP-12b is the only hot Jupiter confirmed to have a decaying orbit. The case of WASP-43b is still under debate. Recent studies preferred or ruled out the orbital decay scenario, but further precise transit timing observations are needed to definitively confirm or refute the period change of WASP-43b. This possibility is given by the Transiting Exoplanet Survey Satellite (TESS) space telescope. In this work, we used the available TESS data, multicolour photometry data obtained with the Multicolor Simultaneous Camera for studying Atmospheres of Transiting exoplanets 2 (MuSCAT2) and literature data to calculate the period change rate of WASP-43b and to improve its precision, and to refine the parameters of the WASP-43 planetary system. Based on the observed-minus-calculated data of 129 mid-transit times in total, covering a time baseline of about 10 yr, we obtained an improved period change rate of (P)over dot = -0.6 +/- 1.2 ms yr(-1) that is consistent with a constant period well within 1 sigma. We conclude that new TESS and MuSCAT2 observations confirm no detection of WASP-43b orbital decay., Erasmus+ grant 2017-1-CZ01-KA203-035562, VEGA grant of the Slovak Academy of Sciences 2/0031/18, ESA PRODEX grant, ELTE University, National Research, Development & Innovation Office (NRDIO) - Hungary 2.3.2-15-2016-00003, City of Szombathely 67.177-21/2016, National Aeronautics & Space Administration (NASA) NAS 5-26555, Gaia Multilateral Agreement, Spanish Ministry of Economics and Competitiveness PGC2018098153-B-C31, Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research (KAKENHI) JP17H04574 JP18H01265 JP18H05439, JST PRESTO grant JPMJPR1775, Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science JP20J21872, Slovak Research and Development Agency APVV-20-0148, Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research (KAKENHI) 18H05442 15H02063 22000005, State Agency for Research of the Spanish MCIU through the 'Center of Excellence Severo Ochoa' award for the Instituto de Astrophysics of Andalusia SEV-2017-0709, European Research Council under the European Union's Horizon 2020 research and innovation program 694513

We present 2,241 exoplanet candidates identified with data from the Transiting Exoplanet Survey Satellite (TESS) during its two-year prime mission. We list these candidates in the TESS Objects of Interest (TOI) Catalog, which includes both new planet candidates found by TESS and previously-known planets recovered by TESS observations. We describe the process used to identify TOIs and investigate the characteristics of the new planet candidates, and discuss some notable TESS planet discoveries. The TOI Catalog includes an unprecedented number of small planet candidates around nearby bright stars, which are well-suited for detailed follow-up observations. The TESS data products for the Prime Mission (Sectors 1-26), including the TOI Catalog, light curves, full-frame images, and target pixel files, are publicly available on the Mikulski Archive for Space Telescopes., Comment: 39 pages, 16 figures. The Prime Mission TOI Catalog is included in the ancillary data as a CSV. For the most up-to-date catalog, refer to https://tess.mit.edu/toi-releases/

We report the discovery and characterization of two transiting planets around the bright M1 V star LP 961-53 (TOI-776, J = 8.5 mag, M = 0.54+-0.03 Msun) detected during Sector 10 observations of the Transiting Exoplanet Survey Satellite (TESS). Combining the TESS photometry with HARPS radial velocities, as well as ground-based follow-up transit observations from MEarth and LCOGT telescopes, we measured for the inner planet, TOI-776 b, a period of 8.25 d, a radius of 1.85+-0.13 Re, and a mass of 4.0+-0.9 Me; and for the outer planet, TOI-776 c, a period of 15.66 d, a radius of 2.02+-0.14 Re, and a mass of 5.3+-1.8 Me. The Doppler data shows one additional signal, with a period of 34 d, associated with the rotational period of the star. The analysis of fifteen years of ground-based photometric monitoring data and the inspection of different spectral line indicators confirm this assumption. The bulk densities of TOI-776 b and c allow for a wide range of possible interior and atmospheric compositions. However, both planets have retained a significant atmosphere, with slightly different envelope mass fractions. Thanks to their location near the radius gap for M dwarfs, we can start to explore the mechanism(s) responsible for the radius valley emergence around low-mass stars as compared to solar-like stars. While a larger sample of well-characterized planets in this parameter space is still needed to draw firm conclusions, we tentatively estimate that the stellar mass below which thermally-driven mass loss is no longer the main formation pathway for sculpting the radius valley is between 0.63 and 0.54 Msun. Due to the brightness of the star, the TOI-776 system is also an excellent target for the James Webb Space Telescope, providing a remarkable laboratory to break the degeneracy in planetary interior models and to test formation and evolution theories of small planets around low-mass stars., Comment: 26 pages, 15 figures, 8 tables. Accepted for publication in Astronomy & Astrophysics

Full list of authors: Soto, M. G.; Anglada-Escudé, G.; Dreizler, S.; Molaverdikhani, K.; Kemmer, J.; Rodríguez-López, C.; Lillo-Box, J.; Pallé, E.; Espinoza, N.; Caballero, J. A.; Quirrenbach, A.; Ribas, I.; Reiners, A.; Narita, N.; Hirano, T.; Amado, P. J.; Béjar, V. J. S.; Bluhm, P.; Burke, C. J.; Caldwell, D. A.; Charbonneau, D.; Cloutier, R.; Collins, K. A.; Cortés-Contreras, M.; Girardin, E.; Guerra, P.; Harakawa, H.; Hatzes, A. P.; Irwin, J.; Jenkins, J. M.; Jensen, E.; Kawauchi, K.; Kotani, T.; Kudo, T.; Kunimoto, M.; Kuzuhara, M.; Latham, D. W.; Montes, D.; Morales, J. C.; Mori, M.; Nelson, R. P.; Omiya, M.; Pedraz, S.; Passegger, V. M.; Rackham, B. V.; Rudat, A.; Schlieder, J. E.; Schöfer, P.; Schweitzer, A.; Selezneva, A.; Stockdale, C.; Tamura, M.; Trifonov, T.; Vanderspek, R.; Watanabe, D., One of the main objectives of the Transiting Exoplanet Survey Satellite (TESS) mission is the discovery of small rocky planets around relatively bright nearby stars. Here, we report the discovery and characterization of the transiting super-Earth planet orbiting LHS 1478 (TOI-1640). The star is an inactive red dwarf (J ∼ 9.6 mag and spectral type m3 V) with mass and radius estimates of 0.20 ± 0.01M· and 0.25 ± 0.01R· , respectively, and an effective temperature of 3381 ± 54 K. It was observed by TESS in four sectors. These data revealed a transit-like feature with a period of 1.949 days. We combined the TESS data with three ground-based transit measurements, 57 radial velocity (RV) measurements from CARMENES, and 13 RV measurements from IRD, determining that the signal is produced by a planet with a mass of 2.33-0.20+0.20 Mâ• and a radius of 1.24-0.05+0.05 Ra• . The resulting bulk density of this planet is 6.67 g cm-3, which is consistent with a rocky planet with an Fe-and MgSiO3-dominated composition. Although the planet would be too hot to sustain liquid water on its surface (its equilibrium temperature is about ∼595 K, suggesting aVenus-like atmosphere), spectroscopic metrics based on the capabilities of the forthcoming James Webb Space Telescope and the fact that the host star is rather inactive indicate that this is one of the most favorable known rocky exoplanets for atmospheric characterization. © 2021 ESO., 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 Ciències 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 iedersachsen, and by the Junta de Andalucía. This paper included data collected by the TESS mission. Funding for the TESS mission is provided by the NASA’s Science Mission Directorate. 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. This work made use of observations from the LCOGT network. LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP), which is funded by the National Science Foundation. We acknowledge financial support from STFC grants ST/P000592/1 and ST/T000341/1, NASA grant NNX17AG24G, the Agencia Estatal de Investigación of the Ministerio de Ciencia, Innovación y Universidades and the ERDF through projects PID2019-109522GB-C5[1:4]/AEI/10.13039/501100011033, PGC2018-098153-B-C3[1,3] and the Centre of Excellence “Severo Ochoa” and “María de Maeztu” awards to the Instituto de Astrofísica de Canarias (SEV-2015-0548), Instituto de Astrofísica de Andalucía (SEV-2017-0709), and Centro de Astrobiología (MDM-2017-0737), the Generalitat de Catalunya/CERCA programme, Grant-in-Aid for JSPS Fellows Grant (JP20J21872), JSPS KAKENHI Grant (22000005, JP15H02063,JP18H01265, JP18H05439, JP18H05442, JP19K14783), JST PRESTO Grant (JPMJPR1775), and University Research Support Grant from the National Astronomical Observatory of Japan.

We analysed 68 candidate planetary systems first identified during Campaigns 5 and 6 (C5 and C6) of the NASA \textit{K2} mission. We set out to validate these systems by using a suite of follow-up observations, including adaptive optics, speckle imaging, and reconnaissance spectroscopy. The overlap between C5 with C16 and C18, and C6 with C17, yields lightcurves with long baselines that allow us to measure the transit ephemeris very precisely, revisit single transit candidates identified in earlier campaigns, and search for additional transiting planets with longer periods not detectable in previous works. Using \texttt{vespa}, we compute false positive probabilities of less than 1\% for 37 candidates orbiting 29 unique host stars and hence statistically validate them as planets. These planets have a typical size of $2.2R_{\oplus}$ and orbital periods between 1.99 and 52.71 days. We highlight interesting systems including a sub-Neptune with the longest period detected by \textit{K2}, sub-Saturns around F stars, several multi-planetary systems in a variety of architectures. These results show that a wealth of planetary systems still remains in the \textit{K2} data, some of which can be validated using minimal follow-up observations and taking advantage of analyses presented in previous catalogs., 25 pages, 12 figures, accepted for publication in MNRAS

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).

AU Microscopii (AU Mic) is the second closest pre main sequence star, at a distance of 9.79 parsecs and with an age of 22 million years. AU Mic possesses a relatively rare and spatially resolved3 edge-on debris disk extending from about 35 to 210 astronomical units from the star, and with clumps exhibiting non-Keplerian motion. Detection of newly formed planets around such a star is challenged by the presence of spots, plage, flares and other manifestations of magnetic activity on the star. Here we report observations of a planet transiting AU Mic. The transiting planet, AU Mic b, has an orbital period of 8.46 days, an orbital distance of 0.07 astronomical units, a radius of 0.4 Jupiter radii, and a mass of less than 0.18 Jupiter masses at 3 sigma confidence. Our observations of a planet co-existing with a debris disk offer the opportunity to test the predictions of current models of planet formation and evolution., Comment: Nature, published June 24th [author spelling name fix]

The Transiting Exoplanet Survey Satellite (TESS) is currently concluding its 2-year primary science mission searching 85% of the sky for transiting exoplanets. TESS has already discovered well over one thousand TESS objects of interest (TOIs), but these candidate exoplanets must be distinguished from astrophysical false positives using other instruments or techniques. The 3-band Multi-color Simultaneous Camera for Studying Atmospheres of Transiting Planets (MuSCAT), as well as the 4-band MuSCAT2, can be used to validate TESS discoveries. Transits of exoplanets are achromatic when observed in multiple bandpasses, while transit depths for false positives often vary with wavelength. We created software tools to simulate MuSCAT/MuSCAT2 TESS follow-up observations and reveal which planet candidates can be efficiently distinguished from blended eclipsing binary (BEB) false positives using these two instruments, and which must be validated using other techniques. We applied our software code to the Barclay et al. (2018) predicted TESS discoveries, as well as to TOIs downloaded from the ExoFOP-TESS website. We estimate that MuSCAT (MuSCAT2 values in parentheses) will be able to use its multi-color capabilities to distinguish BEB false positives for $\sim$17% ($\sim$18%) of all TESS discoveries, and $\sim$13% ($\sim$15%) of $R_{\rm pl} < 4R_\oplus$ discoveries. Our TOI analysis shows that MuSCAT (MuSCAT2) can distinguish BEB false positives for $\sim$55% ($\sim$52%) of TOIs with transit depths greater than 0.001, for $\sim$64% ($\sim$61%) of TOIs with transit depths greater than 0.002, and for $\sim$70% ($\sim$68%) of TOIs with transit depth greater than 0.003. Our work shows that MuSCAT and MuSCAT2 can validate hundreds of $R_{\rm pl} < 4R_\oplus$ candidate exoplanets, thus supporting the TESS mission in achieving its Level 1 Science Requirement., Accepted by PASP, 21 pages, 7 figures, 5 tables, abstract abridged

WASP-33b is a retrograde hot Jupiter with a period of 1.2 days orbiting around a rapidly rotating and pulsating A-type star. A previous study found that the transit chord of WASP-33b had changed slightly from 2008 to 2014 based on Doppler tomographic measurements. They attributed the change to orbital precession caused by the non-zero oblateness of the host star and the misaligned orbit. We aim to confirm and more precisely model the precession behavior using additional Doppler tomographic data of WASP-33b obtained with the High Dispersion Spectrograph on the 8.2m Subaru telescope in 2011, as well as the datasets used in the previous study. Using equations of a long-term orbital precession, we constrain the stellar gravitational quadrupole moment $J_{2}=(9.14\pm 0.51)\times 10^{-5}$ and the angle between the stellar spin axis and the line of sight $i_{\star}=96^{+10}_{-14}$ deg. These values update that the host star is more spherical and viewed more equator than the previous study. We also estimate that the precession period is $\sim$840 years. We also find that the precession amplitude of WASP-33b is $\sim$67 deg and WASP-33b transits in front of the host star for only $\sim$20\% of the whole precession period., 9 pages, 6 figures, published in "advance articles" of the Publications of the Astronomical Society of Japan

The Transiting Exoplanet Survey Satellite, TESS, is currently carrying out an all-sky search for small planets transiting bright stars. In the first year of the TESS survey, steady progress was made in achieving the mission's primary science goal of establishing bulk densities for 50 planets smaller than Neptune. During that year, TESS's observations were focused on the southern ecliptic hemisphere, resulting in the discovery of three mini-Neptunes orbiting the star TOI-125, a V=11.0 K0 dwarf. We present intensive HARPS radial velocity observations, yielding precise mass measurements for TOI-125b, TOI-125c and TOI-125d. TOI-125b has an orbital period of 4.65 days, a radius of $2.726 \pm 0.075 ~\mathrm{R_{\rm E}}$, a mass of $ 9.50 \pm 0.88 ~\mathrm{M_{\rm E}}$ and is near the 2:1 mean motion resonance with TOI-125c at 9.15 days. TOI-125c has a similar radius of $2.759 \pm 0.10 ~\mathrm{R_{\rm E}}$ and a mass of $ 6.63 \pm 0.99 ~\mathrm{M_{\rm E}}$, being the puffiest of the three planets. TOI-125d, has an orbital period of 19.98 days and a radius of $2.93 \pm 0.17~\mathrm{R_{\rm E}}$ and mass $13.6 \pm 1.2 ~\mathrm{M_{\rm E}}$. For TOI-125b and TOI-125d we find unusual high eccentricities of $0.19\pm 0.04$ and $0.17^{+0.08}_{-0.06}$, respectively. Our analysis also provides upper mass limits for the two low-SNR planet candidates in the system; for TOI-125.04 ($R_P=1.36 ~\mathrm{R_{\rm E}}$, $P=$0.53 days) we find a $2\sigma$ upper mass limit of $1.6~\mathrm{M_{\rm E}}$, whereas TOI-125.05 ( $R_P=4.2^{+2.4}_{-1.4} ~\mathrm{R_{\rm E}}$, $P=$ 13.28 days) is unlikely a viable planet candidate with upper mass limit $2.7~\mathrm{M_{\rm E}}$. We discuss the internal structure of the three confirmed planets, as well as dynamical stability and system architecture for this intriguing exoplanet system., Comment: Accepted for publication in MNRAS

We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period Jupiter orbiting a bright (V = 11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 ± 0.078 MJ planet in a grazing transit configuration with an impact parameter of b = 1.17−0.08+0.10. As a result the radius is poorly constrained, 2.03−0.49+0.61RJ. The planet’s distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Qs′ = 107 − 109. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 ± 0.13 MJ and a radius of 1.29 ± 0.02 RJ. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V = 12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V = 12.4 G-type star. It has a mass of 0.79 ±0.06 MJ and a radius of 1.09−0.05+0.08RJ. Despite having the longest orbital period (P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with [Fe / H] ranging from 0.18 to0.24.

About one out of 200 Sun-like stars has a planet with an orbital period shorter than one day: an ultra-short-period planet (Sanchis-ojeda et al. 2014; Winn et al. 2018). All of the previously known ultra-short-period planets are either hot Jupiters, with sizes above 10 Earth radii (Re), or apparently rocky planets smaller than 2 Re. Such lack of planets of intermediate size (the "hot Neptune desert") has been interpreted as the inability of low-mass planets to retain any hydrogen/helium (H/He) envelope in the face of strong stellar irradiation. Here, we report the discovery of an ultra-short-period planet with a radius of 4.6 Re and a mass of 29 Me, firmly in the hot Neptune desert. Data from the Transiting Exoplanet Survey Satellite (Ricker et al. 2015) revealed transits of the bright Sun-like star \starname\, every 0.79 days. The planet's mean density is similar to that of Neptune, and according to thermal evolution models, it has a H/He-rich envelope constituting 9.0^(+2.7)_(-2.9)% of the total mass. With an equilibrium temperature around 2000 K, it is unclear how this "ultra-hot Neptune" managed to retain such an envelope. Follow-up observations of the planet's atmosphere to better understand its origin and physical nature will be facilitated by the star's brightness (Vmag=9.8)., Comment: 26 pages, 10 figures, 3 tables. Published in Nature Astronomy (21/09/2020)

The Neptune desert is a feature seen in the radius-mass-period plane, whereby a notable dearth of short period, Neptune-like planets is found. Here we report the {\it TESS} discovery of a new short-period planet in the Neptune desert, orbiting the G-type dwarf TYC\,8003-1117-1 (TOI-132). {\it TESS} photometry shows transit-like dips at the level of $\sim$1400 ppm occurring every $\sim$2.11 days. High-precision radial velocity follow-up with HARPS confirmed the planetary nature of the transit signal and provided a semi-amplitude radial velocity variation of $\sim$11.5 m s$^{-1}$, which, when combined with the stellar mass of $0.97\pm0.06$ $M_{\odot}$, provides a planetary mass of 22.83$^{+1.81}_{-1.80}$ $M_{\oplus}$. Modeling the {\it TESS} high-quality light curve returns a planet radius of 3.43$^{+0.13}_{-0.14}$ $R_{\oplus}$, and therefore the planet bulk density is found to be 3.11$^{+0.44}_{-0.450}$ g cm$^{-3}$. Planet structure models suggest that the bulk of the planet mass is in the form of a rocky core, with an atmospheric mass fraction of 4.3$^{+1.2}_{-2.3}$\%. TOI-132 b is a {\it TESS} Level 1 Science Requirement candidate, and therefore priority follow-up will allow the search for additional planets in the system, whilst helping to constrain low-mass planet formation and evolution models, particularly valuable for better understanding the Neptune desert., 12 pages, 10 figures, 4 tables. Submitted to MNRAS. Comments welcome. Missing labels, Typos fixed

We present new transit observations of the hot Jupiter WASP-74 b ($T_\mathrm{eq} \sim$ 1860 K) using the high-resolution spectrograph HARPS-N and the multi-colour simultaneous imager MuSCAT2. We refine the orbital properties of the planet and its host star, and measure its obliquity for the first time. The measured sky-projected angle between the stellar spin-axis and the planet's orbital axis is compatible with an orbit well-aligned with the equator of the host star ($\lambda = 0.77\pm0.99 \mathrm{deg}$). We are not able to detect any absorption feature of H$\alpha$, or any other atomic spectral features, in its high-resolution transmission spectra due to low S/N at the line cores. Despite previous claims regarding the presence of strong optical absorbers such TiO and VO gases in the atmosphere of WASP-74 b, the new ground-based photometry combined with a reanalysis of previously reported observations from the literature shows a slope in the low-resolution transmission spectrum steeper than expected from Rayleigh scattering alone., Comment: Accepted for publication in Astronomy & Astrophysics. 12 pages, 8 figures, 5 tables

All authors: Bluhm, P.; Luque, R.; Espinoza, N.; Pallé, E.; Caballero, J. A.; Dreizler, S.; Livingston, J. H.; Mathur, S.; Quirrenbach, A.; Stock, S.; Van Eylen, V.; Nowak, G.; López, E. D.; Csizmadia, Sz.; Zapatero Osorio, M. R.; Schöfer, P.; Lillo-Box, J.; Oshagh, M.; González-Álvarez, E.; Amado, P. J.; Barrado, D.; Béjar, V. J. S.; Cale, B.; Chaturvedi, P.; Cifuentes, C.; Cochran, W. D.; Collins, K. A.; Collins, K. I.; Cortés-Contreras, M.; Díez Alonso, E.; El Mufti, M.; Ercolino, A.; Fridlund, M.; Gaidos, E.; García, R. A.; Georgieva, I.; González-Cuesta, L.; Guerra, P.; Hatzes, A. P.; Henning, Th.; Herrero, E.; Hidalgo, D.; Isopi, G.; Jeffers, S. V.; Jenkins, J. M.; Jensen, E. L. N.; Kábath, P.; Kaminski, A.; Kemmer, J.; Korth, J.; Kossakowski, D.; Kürster, M.; Lafarga, M.; Mallia, F.; Montes, D.; Morales, J. C.; Morales-Calderón, M.; Murgas, F.; Narita, N.; Passegger, V. M.; Pedraz, S.; Persson, C. M.; Plavchan, P.; Rauer, H.; Redfield, S.; Reffert, S.; Reiners, A.; Ribas, I.; Ricker, G. R.; Rodríguez-López, C.; Santos, A. R. G.; Seager, S.; Schlecker, M.; Schweitzer, A.; Shan, Y.; Soto, M. G.; Subjak, J.; Tal-Or, L.; Trifonov, T.; Vanaverbeke, S.; Vanderspek, R.; Wittrock, J.; Zechmeister, M.; Zohrabi, F., We report the confirmation of a transiting planet around the bright weakly active M0.5 V star TOI-1235 (TYC 4384-1735-1, V ≈ 11.5 mag), whose transit signal was detected in the photometric time series of sectors 14, 20, and 21 of the TESS space mission. We confirm the planetary nature of the transit signal, which has a period of 3.44 d, by using precise RV measurements with the CARMENES, HARPS-N, and iSHELL spectrographs, supplemented by high-resolution imaging and ground-based photometry. A comparison of the properties derived for TOI-1235 b with theoretical models reveals that the planet has a rocky composition, with a bulk density slightly higher than that of Earth. In particular, we measure a mass of Mp = 5.9 ± 0.6 M⊕ and a radius of Rp = 1.69 ± 0.08 R⊕ , which together result in a density of ρp = 6.7- 1.1+ 1.3 g cm-3. When compared with other well-characterized exoplanetary systems, the particular combination of planetary radius and mass places our discovery in the radius gap, which is a transition region between rocky planets and planets with significant atmospheric envelopes. A few examples of planets occupying the radius gap are known to date. While the exact location of the radius gap for M dwarfs is still a matter of debate, our results constrain it to be located at around 1.7 R⊕ or larger at the insolation levels received by TOI-1235 b (~60 S⊕ ). This makes it an extremely interesting object for further studies of planet formation and atmospheric evolution. © ESO 2020., CARMENES is an instrument for the Centro Astronomico Hispano-Aleman de Calar Alto (CAHA, Almeria, Spain). CARMENES is 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, Institut 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 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. 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 (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. We acknowledge financial support from the European Research Council under the Horizon 2020 Framework Program via the ERC Advanced Grant Origins 83 24 28, the Deutsche Forschungsgemeinschaft through projects RE 281/32-1, RE 1664/14-1, RE 2694/4-1, and RA714/14-1, PA525/18-1, PA525/19-1 within the Schwerpunkt SPP 1992, the Agencia Estatal de Investigacion of the Ministerio de Ciencia, Innovacion y Universidades and the European FEDER/ERF funds through projects PGC2018-098153-B-C31, ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, AYA2016-79425-C3-1/2/3P, AYA2015-69350-C3-2-P, RYC-2015-17697, and BES-2017-082610, the Centre of Excellence "Severo Ochoa" and "Maria de Maeztu" awards to the Instituto de Astrofisica de Canarias (SEV-2015-0548), Instituto de Astrofisica de Andalucia (SEV-2017-0709), and Centro de Astrobiologia (MDM-2017-0737), the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant 713673, the Centre national d'etudes spatiales through grants PLATO and GOLF, the Czech Academy of Sciences through grant LTT20015, NASA through grants NNX17AF27G and NNX17AG24G, JSPS KAKENHI through grants JP18H01265 and JP18H05439, JST PRESTO through grant JPMJPR1775, the Fundacion Bancaria "la Caixa" through grant INPhINIT LCF/BQ/IN17/11620033, and the Generalitat de Catalunya/CERCA programme. NESSI was funded by the NASA Exoplanet Exploration Program and the NASA Ames Research Center and built at the Ames Research Center. The authors are honored to be permitted to conduct observations on Iolkam Du'ag (Kitt Peak), a mountain within the Tohono O'odham Nation with particular significance to the Tohono O'odham people. This work made use of observations from the LCOGT network and the following software: astrasens, AstroImageJ, Banzai, batman, caracal, emcee, juliet, serval, TESS Transit Finder, tpfplotter, Yabi, and the python packages astropy, lightkurve, matplotlib, and numpy. We thank the SuperWASP team and J. Sanz-Forcada for sharing unpublished information with us. Special thanks to Ismael Pessa for all their support through this work.

Astronomers have discovered thousands of planets outside the solar system, most of which orbit stars that will eventually evolve into red giants and then into white dwarfs. During the red giant phase, any close-orbiting planets will be engulfed by the star, but more distant planets can survive this phase and remain in orbit around the white dwarf. Some white dwarfs show evidence for rocky material floating in their atmospheres, in warm debris disks, or orbiting very closely, which has been interpreted as the debris of rocky planets that were scattered inward and tidally disrupted. Recently, the discovery of a gaseous debris disk with a composition similar to ice giant planets demonstrated that massive planets might also find their way into tight orbits around white dwarfs, but it is unclear whether the planets can survive the journey. So far, the detection of intact planets in close orbits around white dwarfs has remained elusive. Here, we report the discovery of a giant planet candidate transiting the white dwarf WD 1856+534 (TIC 267574918) every 1.4 days. The planet candidate is roughly the same size as Jupiter and is no more than 14 times as massive (with 95% confidence). Other cases of white dwarfs with close brown dwarf or stellar companions are explained as the consequence of common-envelope evolution, wherein the original orbit is enveloped during the red-giant phase and shrinks due to friction. In this case, though, the low mass and relatively long orbital period of the planet candidate make common-envelope evolution less likely. Instead, the WD 1856+534 system seems to demonstrate that giant planets can be scattered into tight orbits without being tidally disrupted, and motivates searches for smaller transiting planets around white dwarfs., Comment: 50 pages, 12 figures, 2 tables. Published in Nature on Sept. 17, 2020. The final authenticated version is available online at: https://www.nature.com/articles/s41586-020-2713-y

We report the discovery of a planetary system orbiting TOI-763 (aka CD-39 7945), a $V=10.2$, high proper motion G-type dwarf star that was photometrically monitored by the TESS space mission in Sector 10. We obtain and model the stellar spectrum and find an object slightly smaller than the Sun, and somewhat older, but with a similar metallicity. Two planet candidates were found in the light curve to be transiting the star. Combining TESS transit photometry with HARPS high-precision radial velocity follow-up measurements confirm the planetary nature of these transit signals. We determine masses, radii, and bulk densities of these two planets. A third planet candidate was discovered serendipitously in the radial velocity data. The inner transiting planet,TOI-763 b, has an orbital period of $P_\mathrm{b}$ = 5.6~days, a mass of $M_\mathrm{b}$ = $9.8\pm0.8$ $M_\oplus$, and a radius of $R_\mathrm{b}$ = $2.37\pm0.10$ $R_\oplus$. The second transiting planet,TOI-763 c, has an orbital period of $P_\mathrm{c}$ = 12.3~days, a mass of $M_\mathrm{c}$ = $9.3\pm1.0$ $M_\oplus$, and a radius of $R_\mathrm{c}$ = $2.87\pm0.11$ $R_\oplus$. We find the outermost planet candidate to orbit the star with a period of $\sim$48~days. If confirmed as a planet it would have a minimum mass of $M_\mathrm{d}$ = $9.5\pm1.6$ $M_\oplus$. We investigated the TESS light curve in order to search for a mono transit by planet~d without success. We discuss the importance and implications of this planetary system in terms of the geometrical arrangements of planets orbiting G-type stars.