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1. JWST/NIRISS Reveals the Water-rich 'Steam World' Atmosphere of GJ 9827 d

Author: Caroline Piaulet-Ghorayeb, Björn Benneke, Michael Radica, Eshan Raul, Louis-Philippe Coulombe, Eva-Maria Ahrer, Daria Kubyshkina, Ward S. Howard, Joshua Krissansen-Totton, Ryan J. MacDonald, Pierre-Alexis Roy, Amy Louca, Duncan Christie, Marylou Fournier-Tondreau, Romain Allart, Yamila Miguel, Hilke E. Schlichting, Luis Welbanks, Charles Cadieux, Caroline Dorn, Thomas M. Evans-Soma, Jonathan J. Fortney, Raymond Pierrehumbert, David Lafrenière, Lorena Acuña, Thaddeus Komacek, Hamish Innes, Thomas G. Beatty, Ryan Cloutier, René Doyon, Anna Gagnebin, Cyril Gapp, and Heather A. Knutson
Subjects: Exoplanet atmospheres, Exoplanet atmospheric composition, Exoplanet atmospheric evolution, Exoplanet structure, Planetary atmospheres, Exoplanet astronomy, Astrophysics, QB460-466
Abstract: With sizable volatile envelopes but smaller radii than the solar system ice giants, sub-Neptunes have been revealed as one of the most common types of planet in the galaxy. While the spectroscopic characterization of larger sub-Neptunes (2.5–4 R _⊕ ) has revealed hydrogen-dominated atmospheres, smaller sub-Neptunes (1.6–2.5 R _⊕ ) could either host thin, rapidly evaporating, hydrogen-rich atmospheres or be stable, metal-rich “water worlds” with high mean molecular weight atmospheres and a fundamentally different formation and evolutionary history. Here, we present the 0.6–2.8 μ m JWST/NIRISS/SOSS transmission spectrum of GJ 9827 d, the smallest (1.98 R _⊕ ) warm ( T _eq,A=0.3 ∼ 620 K) sub-Neptune where atmospheric absorbers have been detected to date. Our two transit observations with NIRISS/SOSS, combined with the existing HST/WFC3 spectrum, enable us to break the clouds–metallicity degeneracy. We detect water in a highly metal-enriched “steam world” atmosphere (O/H of ∼4 by mass and H _2 O found to be the background gas with a volume mixing ratio of >31%). We further show that these results are robust to stellar contamination through the transit light source effect. We do not detect escaping metastable He, which, combined with previous nondetections of escaping He and H, supports the steam atmosphere scenario. In water-rich atmospheres, hydrogen loss driven by water photolysis happens predominantly in the ionized form, which eludes observational constraints. We also detect several flares in the NIRISS/SOSS light curves with far-UV energies of the order of 10 ^30 erg, highlighting the active nature of the star. Further atmospheric characterization of GJ 9827 d probing carbon or sulfur species could reveal the origin of its high metal enrichment.
Published: 2024
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2. Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS

Author: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L’Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, and Diana Valencia
Subjects: Exoplanets, Habitable planets, Planetary atmospheres, Super Earths, Ocean planets, Mini Neptunes, Astrophysics, QB460-466
Abstract: LHS 1140 b is the second-closest temperate transiting planet to Earth with an equilibrium temperature low enough to support surface liquid water. At 1.730 ± 0.025 R _⊕ , LHS 1140 b falls within the radius valley separating H _2 -rich mini-Neptunes from rocky super-Earths. Recent mass and radius revisions indicate a bulk density significantly lower than expected for an Earth-like rocky interior, suggesting that LHS 1140 b could be either a mini-Neptune with a small envelope of hydrogen (∼0.1% by mass) or a water world (9%–19% water by mass). Atmospheric characterization through transmission spectroscopy can readily discern between these two scenarios. Here we present two JWST/NIRISS transit observations of LHS 1140 b, one of which captures a serendipitous transit of LHS 1140 c. The combined transmission spectrum of LHS 1140 b shows a telltale spectral signature of unocculted faculae (5.8 σ ), covering ∼20% of the visible stellar surface. Besides faculae, our spectral retrieval analysis reveals tentative evidence of residual spectral features, best fit by Rayleigh scattering from a N _2 -dominated atmosphere (2.3 σ ), irrespective of the consideration of atmospheric hazes. We also show through Global Climate Models (GCMs) that H _2 -rich atmospheres of various compositions (100×, 300×, 1000× solar metallicity) are ruled out to >10 σ . The GCM calculations predict that water clouds form below the transit photosphere, limiting their impact on transmission data. Our observations suggest that LHS 1140 b is either airless or, more likely, surrounded by an atmosphere with a high mean molecular weight. Our tentative evidence of a N _2 -rich atmosphere provides strong motivation for future transmission spectroscopy observations of LHS 1140 b.
Published: 2024
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3. New Mass and Radius Constraints on the LHS 1140 Planets: LHS 1140 b Is either a Temperate Mini-Neptune or a Water World

Author: Charles Cadieux, Mykhaylo Plotnykov, René Doyon, Diana Valencia, Farbod Jahandar, Lisa Dang, Martin Turbet, Thomas J. Fauchez, Ryan Cloutier, Collin Cherubim, Étienne Artigau, Neil J. Cook, Billy Edwards, Tim Hallatt, Benjamin Charnay, François Bouchy, Romain Allart, Lucile Mignon, Frédérique Baron, Susana C. C. Barros, Björn Benneke, B. L. Canto Martins, Nicolas B. Cowan, J. R. De Medeiros, Xavier Delfosse, Elisa Delgado-Mena, Xavier Dumusque, David Ehrenreich, Yolanda G. C. Frensch, J. I. González Hernández, Nathan C. Hara, David Lafrenière, Gaspare Lo Curto, Lison Malo, Claudio Melo, Dany Mounzer, Vera Maria Passeger, Francesco Pepe, Anne-Sophie Poulin-Girard, Nuno C. Santos, Danuta Sosnowska, Alejandro Suárez Mascareño, Simon Thibault, Valentina Vaulato, Gregg A. Wade, and François Wildi
Subjects: Exoplanets, Habitable planets, Super Earths, M dwarf stars, Planetary interior, Astrophysics, QB460-466
Abstract: The two-planet transiting system LHS 1140 has been extensively observed since its discovery in 2017, notably with Spitzer, HST, TESS, and ESPRESSO, placing strong constraints on the parameters of the M4.5 host star and its small temperate exoplanets, LHS 1140 b and c. Here, we reanalyze the ESPRESSO observations of LHS 1140 with the novel line-by-line framework designed to fully exploit the radial velocity content of a stellar spectrum while being resilient to outlier measurements. The improved radial velocities, combined with updated stellar parameters, consolidate our knowledge of the mass of LHS 1140 b (5.60 ± 0.19 M _⊕ ) and LHS 1140 c (1.91 ± 0.06 M _⊕ ) with an unprecedented precision of 3%. Transits from Spitzer, HST, and TESS are jointly analyzed for the first time, allowing us to refine the planetary radii of b (1.730 ± 0.025 R _⊕ ) and c (1.272 ± 0.026 R _⊕ ). Stellar abundance measurements of refractory elements (Fe, Mg, and Si) obtained with NIRPS are used to constrain the internal structure of LHS 1140 b. This planet is unlikely to be a rocky super-Earth, as previously reported, but rather a mini-Neptune with a ∼0.1% H/He envelope by mass or a water world with a water-mass fraction between 9% and 19%, depending on the atmospheric composition and relative abundance of Fe and Mg. While the mini-Neptune case would not be habitable, a water-abundant LHS 1140 b potentially has habitable surface conditions according to 3D global climate models, suggesting liquid water at the substellar point for atmospheres with relatively low CO _2 concentration, from Earth-like to a few bars.
Published: 2024
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4. Modeling Multiple Radius Valley Emergence Mechanisms with Multitransiting Systems

Author: Madison VanWyngarden and Ryan Cloutier
Subjects: Exoplanets, Exoplanet evolution, Exoplanet formation, Planetary system evolution, Star-planet interactions, Astronomy, QB1-991
Abstract: Close-in planets smaller than Neptune form two distinct populations composed of rocky super-Earths and sub-Neptunes that may host primordial H/He envelopes. The origin of the radius valley separating these two planet populations remains an open question and has been posited to emerge either directly from the planet formation process or via subsequent atmospheric escape. Multitransiting systems that span the radius valley are known to be useful diagnostics of XUV-driven mass loss. Here, we extend this framework to test XUV-driven photoevaporation, core-powered mass loss, and an accretion-limited primordial radius valley model. Focusing on multitransiting systems allows us to eliminate unobservable quantities that are shared within individual systems such as stellar XUV luminosity histories and the properties of the protoplanetary disk. We test each proposed radius valley emergence mechanism on all 221 known multitransiting systems and calculate the minimum masses of the systems’ enveloped planets to be consistent with the models. We compare our model predictions to 75 systems with measured masses and find that the majority of systems can be explained by any of the three proposed mechanisms. We also examine model consistency as a function of stellar mass and stellar metallicity but find no significant trends. More multitransiting systems with mass characterizations are required before multitransiting systems can serve as a viable diagnostic of radius valley emergence models. Our software for the model evaluations presented herein is available on GitHub and may be applied to future multitransiting system discoveries.
Published: 2024
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5. Validation of a Third Planet in the LHS 1678 System

Author: Michele L. Silverstein, Thomas Barclay, Joshua E. Schlieder, Karen A. Collins, Richard P. Schwarz, Benjamin J. Hord, Jason F. Rowe, Ethan Kruse, Nicola Astudillo-Defru, Xavier Bonfils, Douglas A. Caldwell, David Charbonneau, Ryan Cloutier, Kevin I. Collins, Tansu Daylan, William Fong, Jon M. Jenkins, Michelle Kunimoto, Scott McDermott, Felipe Murgas, Enric Palle, George R. Ricker, Sara Seager, Avi Shporer, Evan Tey, Roland Vanderspek, and Joshua N. Winn
Subjects: Exoplanet systems, Transit photometry, Transit timing variation method, M dwarf stars, Astronomy, QB1-991
Abstract: The nearby LHS 1678 (TOI-696) system contains two confirmed planets and a wide-orbit, likely brown-dwarf companion, which orbit an M2 dwarf with a unique evolutionary history. The host star occupies a narrow “gap” in the Hertzsprung–Russell diagram lower main sequence, associated with the M dwarf fully convective boundary and long-term luminosity fluctuations. This system is one of only about a dozen M dwarf multiplanet systems to date that hosts an ultra-short-period planet (USP). Here we validate and characterize a third planet in the LHS 1678 system using TESS Cycle 1 and 3 data and a new ensemble of ground-based light curves. LHS 1678 d is a 0.98 ± 0.07 R _⊕ planet in a 4.97 day orbit, with an insolation flux of ${9.1}_{-0.8}^{+0.9}\,{S}_{\oplus }$ . These properties place it near 4:3 mean motion resonance with LHS 1678 c and in company with LHS 1678 c in the Venus zone. LHS 1678 c and d are also twins in size and predicted mass, making them a powerful duo for comparative exoplanet studies. LHS 1678 d joins its siblings as another compelling candidate for atmospheric measurements with the JWST and mass measurements using high-precision radial velocity techniques. Additionally, USP LHS 1678 b breaks the “peas-in-a-pod” trend in this system although additional planets could fill in the “pod” beyond its orbit. LHS 1678's unique combination of system properties and their relative rarity among the ubiquity of compact multiplanet systems around M dwarfs makes the system a valuable benchmark for testing theories of planet formation and evolution.
Published: 2024
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6. Comprehensive High-resolution Chemical Spectroscopy of Barnard’s Star with SPIRou

Author: Farbod Jahandar, René Doyon, Étienne Artigau, Neil J. Cook, Charles Cadieux, David Lafrenière, Thierry Forveille, Jean-François Donati, Pascal Fouqué, Andrés Carmona, Ryan Cloutier, Paul Cristofari, Eric Gaidos, João Gomes da Silva, Lison Malo, Eder Martioli, J.-D. do Nascimento Jr., Stefan Pelletier, Thomas Vandal, and Kim Venn
Subjects: M dwarf stars, Low mass stars, Stellar atmospheres, Chemical abundances, Abundance ratios, Metallicity, Astrophysics, QB460-466
Abstract: Determination of fundamental parameters of stars impacts all fields of astrophysics, from galaxy evolution to constraining the internal structure of exoplanets. This paper presents a detailed spectroscopic analysis of Barnard’s star (otherwise known as Gl 699) that compares an exceptionally high-quality (an average signal-to-noise ratio of ∼1000 in the entire domain), high-resolution near-infrared (NIR) spectrum taken with Canada-France-Hawaii Telescope/SPIRou to PHOENIX-ACES stellar atmosphere models. The observed spectrum shows thousands of lines not identified in the models with a similarly large number of lines present in the model but not in the observed data. We also identify several other caveats, such as continuum mismatch, unresolved contamination, and spectral lines significantly shifted from their expected wavelengths; all of these can be a source of bias for the determination of abundance. Out of >10 ^4 observed lines in the NIR that could be used for chemical spectroscopy, we identify a short list of a few hundred lines that are reliable. We present a novel method for determining the effective temperature ( T _eff ) and overall metallicity of slowly rotating M dwarfs that uses several groups of lines as opposed to bulk spectral fitting methods. With this method, we infer T _eff = 3231 ± 21 K for Barnard's star, consistent with the value of 3238 ± 11 K inferred from the interferometric method. We also provide measurements of the abundance of 15 different elements for Barnard's star, including the abundances of four elements (K, O, Y, Th) never reported before for this star. This work emphasizes the need to improve current atmosphere models to fully exploit the NIR domain for chemical spectroscopy analysis.
Published: 2024
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7. Identification of the Top TESS Objects of Interest for Atmospheric Characterization of Transiting Exoplanets with JWST

Author: Benjamin J. Hord, Eliza M.-R. Kempton, Thomas M. Evans-Soma, David W. Latham, David R. Ciardi, Diana Dragomir, Knicole D. Colón, Gabrielle Ross, Andrew Vanderburg, Zoe L. de Beurs, Karen A. Collins, Cristilyn N. Watkins, Jacob Bean, Nicolas B. Cowan, Tansu Daylan, Caroline V. Morley, Jegug Ih, David Baker, Khalid Barkaoui, Natalie M. Batalha, Aida Behmard, Alexander Belinski, Zouhair Benkhaldoun, Paul Benni, Krzysztof Bernacki, Allyson Bieryla, Avraham Binnenfeld, Pau Bosch-Cabot, François Bouchy, Valerio Bozza, Rafael Brahm, Lars A. Buchhave, Michael Calkins, Ashley Chontos, Catherine A. Clark, Ryan Cloutier, Marion Cointepas, Kevin I. Collins, Dennis M. Conti, Ian J. M. Crossfield, Fei Dai, Jerome P. de Leon, Georgina Dransfield, Courtney Dressing, Adam Dustor, Gilbert Esquerdo, Phil Evans, Sergio B. Fajardo-Acosta, Jerzy Fiołka, Raquel Forés-Toribio, Antonio Frasca, Akihiko Fukui, Benjamin Fulton, Elise Furlan, Tianjun Gan, Davide Gandolfi, Mourad Ghachoui, Steven Giacalone, Emily A. Gilbert, Michaël Gillon, Eric Girardin, Erica Gonzales, Ferran Grau Horta, Joao Gregorio, Michael Greklek-McKeon, Pere Guerra, J. D. Hartman, Coel Hellier, Ian Helm, Krzysztof G. Hełminiak, Thomas Henning, Michelle L. Hill, Keith Horne, Andrew W. Howard, Steve B. Howell, Daniel Huber, Giovanni Isopi, Emmanuel Jehin, Jon M. Jenkins, Eric L. N. Jensen, Marshall C. Johnson, Andrés Jordán, Stephen R. Kane, John F. Kielkopf, Vadim Krushinsky, Sławomir Lasota, Elena Lee, Pablo Lewin, John H. Livingston, Jack Lubin, Michael B. Lund, Franco Mallia, Christopher R. Mann, Giuseppi Marino, Nataliia Maslennikova, Bob Massey, Rachel Matson, Elisabeth Matthews, Andrew W. Mayo, Tsevi Mazeh, Kim K. McLeod, Edward J. Michaels, Teo Močnik, Mayuko Mori, Georgia Mraz, Jose A. Muñoz, Norio Narita, Krupa Natarajan, Louise Dyregaard Nielsen, Hugh Osborn, Enric Palle, Aviad Panahi, Riccardo Papini, Peter Plavchan, Alex S. Polanski, Adam Popowicz, Francisco J. Pozuelos, Samuel N. Quinn, Don J. Radford, Phillip A. Reed, Howard M. Relles, Malena Rice, Paul Robertson, Joseph E. Rodriguez, Lee J. Rosenthal, Ryan A. Rubenzahl, Nicole Schanche, Joshua Schlieder, Richard P. Schwarz, Ramotholo Sefako, Avi Shporer, Alessandro Sozzetti, Gregor Srdoc, Chris Stockdale, Alexander Tarasenkov, Thiam-Guan Tan, Mathilde Timmermans, Eric B. Ting, Judah Van Zandt, JP Vignes, Ian Waite, Noriharu Watanabe, Lauren M. Weiss, Justin Wittrock, George Zhou, Carl Ziegler, and Shay Zucker
Subjects: Exoplanet astronomy, Exoplanet atmospheres, Transit photometry, James Webb Space Telescope, Exoplanets, Astronomy, QB1-991
Abstract: JWST has ushered in an era of unprecedented ability to characterize exoplanetary atmospheres. While there are over 5000 confirmed planets, more than 4000 Transiting Exoplanet Survey Satellite (TESS) planet candidates are still unconfirmed and many of the best planets for atmospheric characterization may remain to be identified. We present a sample of TESS planets and planet candidates that we identify as “best-in-class” for transmission and emission spectroscopy with JWST. These targets are sorted into bins across equilibrium temperature T _eq and planetary radius R _p and are ranked by a transmission and an emission spectroscopy metric (TSM and ESM, respectively) within each bin. We perform cuts for expected signal size and stellar brightness to remove suboptimal targets for JWST. Of the 194 targets in the resulting sample, 103 are unconfirmed TESS planet candidates, also known as TESS Objects of Interest (TOIs). We perform vetting and statistical validation analyses on these 103 targets to determine which are likely planets and which are likely false positives, incorporating ground-based follow-up from the TESS Follow-up Observation Program to aid the vetting and validation process. We statistically validate 18 TOIs, marginally validate 31 TOIs to varying levels of confidence, deem 29 TOIs likely false positives, and leave the dispositions for four TOIs as inconclusive. Twenty-one of the 103 TOIs were confirmed independently over the course of our analysis. We intend for this work to serve as a community resource and motivate formal confirmation and mass measurements of each validated planet. We encourage more detailed analysis of individual targets by the community.
Published: 2024
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8. FORECASTOR. I. Finding Optics Requirements and Exposure Times for the Cosmological Advanced Survey Telescope for Optical and UV Research Mission

Author: Isaac Cheng, Tyrone E. Woods, Patrick Côté, Jennifer Glover, Dhananjhay Bansal, Melissa Amenouche, Madeline A. Marshall, Laurie Amen, John Hutchings, Laura Ferrarese, Kim A. Venn, Michael Balogh, Simon Blouin, Ryan Cloutier, Nolan Dickson, Sarah Gallagher, Martin Hellmich, Vincent Hénault-Brunet, Viraja Khatu, Cameron Lawlor-Forsyth, Cameron Morgan, Harvey Richer, Marcin Sawicki, and Robert Sorba
Subjects: Galaxies, M stars, Photometry, Proper motions, Ultraviolet telescopes, White dwarf stars, Astronomy, QB1-991
Abstract: The Cosmological Advanced Survey Telescope for Optical and ultraviolet Research (CASTOR) is a proposed Canadian-led 1 m class space telescope that will carry out ultraviolet and blue optical wide-field imaging, spectroscopy, and photometry. CASTOR will provide an essential bridge in the post-Hubble era, preventing a protracted UV-optical gap in space astronomy and enabling an enormous range of discovery opportunities from the solar system to the nature of the cosmos, in conjunction with the other great wide-field observatories of the next decade (e.g., Euclid, Roman, Vera Rubin). FORECASTOR (Finding Optics Requirements and Exposure times for CASTOR) will supply a coordinated suite of mission-planning tools that will serve as the one-stop shop for proposal preparation, data reduction, and analysis for the CASTOR mission. We present the first of these tools: a pixel-based, user-friendly, extensible, multi-mission exposure time calculator built in Python, including a modern browser-based graphical user interface that updates in real time. We then provide several illustrative examples of FORECASTOR’s use that advance the design of planned legacy surveys for the CASTOR mission: a search for the most massive white dwarfs in the Magellanic Clouds, a study of the frequency of flaring activity in M stars and their distribution and impacts on habitability of exoplanets, mapping the proper motions of faint stars in the Milky Way, wide and deep galaxy surveys, and time-domain studies of active galactic nuclei.
Published: 2024
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9. Two Warm Super-Earths Transiting the Nearby M Dwarf TOI-2095

Author: Elisa V. Quintana, Emily A. Gilbert, Thomas Barclay, Michele L. Silverstein, Joshua E. Schlieder, Ryan Cloutier, Samuel N. Quinn, Joseph E. Rodriguez, Andrew Vanderburg, Benjamin J. Hord, Dana R. Louie, Colby Ostberg, Stephen R. Kane, Kelsey Hoffman, Jason F. Rowe, Giada N. Arney, Prabal Saxena, Taran Richardson, Matthew S. Clement, Nicholas M. Kartvedt, Fred C. Adams, Marcus Alfred, Travis Berger, Allyson Bieryla, Paul Bonney, Patricia Boyd, Charles Cadieux, Douglas Caldwell, David R. Ciardi, David Charbonneau, Karen A. Collins, Knicole D. Colón, Dennis M. Conti, Mario Di Sora, Shawn Domagal-Goldman, Jessie Dotson, Thomas Fauchez, Erica J. Gonzales, Maximilian N. Günther, Christina Hedges, Giovanni Isopi, Erika Kohler, Ravi Kopparapu, Veselin B. Kostov, Jeffrey A. Larsen, Eric Lopez, Franco Mallia, Avi Mandell, Susan E. Mullally, Rishi R. Paudel, Brian P. Powell, George R. Ricker, Boris S. Safonov, Richard P. Schwarz, Ramotholo Sefako, Keivan G. Stassun, Robert Wilson, Joshua N. Winn, and Roland K. Vanderspek
Subjects: Exoplanets, M stars, Astronomy, QB1-991
Abstract: We report the detection and validation of two planets orbiting TOI-2095 (TIC 235678745). The host star is a 3700 K M1V dwarf with a high proper motion. The star lies at a distance of 42 pc in a sparsely populated portion of the sky and is bright in the infrared ( K = 9). With data from 24 sectors of observation during Cycles 2 and 4 of the Transiting Exoplanet Survey Satellite, TOI-2095 exhibits two sets of transits associated with super-Earth-sized planets. The planets have orbital periods of 17.7 days and 28.2 days and radii of 1.30 R _⊕ and 1.39 R _⊕ , respectively. Archival data, preliminary follow-up observations, and vetting analyses support the planetary interpretation of the detected transit signals. The pair of planets have estimated equilibrium temperatures of approximately 400 K, with stellar insolations of 3.23 and 1.73 S _⊕ , placing them in the Venus zone. The planets also lie in a radius regime signaling the transition between rock-dominated and volatile-rich compositions. They are thus prime targets for follow-up mass measurements to better understand the properties of warm, transition-radius planets. The relatively long orbital periods of these two planets provide crucial data that can help shed light on the processes that shape the composition of small planets orbiting M dwarfs.
Published: 2023
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10. HST/WFC3 Light Curve Supports a Terrestrial Composition for the Closest Exoplanet to Transit an M Dwarf

Author: Emily K. Pass, Jennifer G. Winters, David Charbonneau, Aurelia Balkanski, Nikole Lewis, Maura Lally, Jacob L. Bean, Ryan Cloutier, and Jason D. Eastman
Subjects: Exoplanet astronomy, Transit photometry, Exoplanets, M dwarf stars, Transits, HST photometry, Astronomy, QB1-991
Abstract: Previous studies of the exoplanet LTT 1445Ac concluded that the light curve from the Transiting Exoplanet Survey Satellite (TESS) was consistent with both grazing and nongrazing geometries. As a result, the radius and hence density of the planet remained unknown. To resolve this ambiguity, we observed the LTT 1445 system for six spacecraft orbits of the Hubble Space Telescope (HST) using WFC3/UVIS imaging in spatial scan mode, including one partial transit of LTT 1445Ac. This imaging produces resolved light curves of each of the three stars in the LTT 1445 system. We confirm that the planet transits LTT 1445A and that LTT 1445C is the source of the rotational modulation seen in the TESS light curve, and we refine the estimate of the dilution factor for the TESS data. We perform a joint fit to the TESS and HST observations, finding that the transit of LTT 1445Ac is not grazing with 97% confidence. We measure a planetary radius of ${1.07}_{-0.07}^{+0.10}\,{R}_{\oplus }$ . Combined with previous radial velocity observations, our analysis yields a planetary mass of 1.37 ± 0.19 M _⊕ and a planetary density of ${5.9}_{-1.5}^{+1.8}$ g cm ^−3 . LTT 1445Ac is likely an Earth analog with respect to its mass and radius, albeit with a higher instellation, and is therefore an exciting target for future atmospheric studies.
Published: 2023
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11. Three Long-period Transiting Giant Planets from TESS

Author: Rafael Brahm, Solène Ulmer-Moll, Melissa J. Hobson, Andrés Jordán, Thomas Henning, Trifon Trifonov, Matías I. Jones, Martin Schlecker, Nestor Espinoza, Felipe I. Rojas, Pascal Torres, Paula Sarkis, Marcelo Tala, Jan Eberhardt, Diana Kossakowski, Diego J. Muñoz, Joel D. Hartman, Gavin Boyle, Vincent Suc, François Bouchy, Adrien Deline, Guillaume Chaverot, Nolan Grieves, Monika Lendl, Olga Suarez, Tristan Guillot, Amaury H. M. J. Triaud, Nicolas Crouzet, Georgina Dransfield, Ryan Cloutier, Khalid Barkaoui, Rick P. Schwarz, Chris Stockdale, Mallory Harris, Ismael Mireles, Phil Evans, Andrew W. Mann, Carl Ziegler, Diana Dragomir, Steven Villanueva, Christoph Mordasini, George Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Michael Vezie, Allison Youngblood, Tansu Daylan, Karen A. Collins, Douglas A. Caldwell, David R. Ciardi, Enric Palle, and Felipe Murgas
Subjects: Exoplanets, Extrasolar gaseous giant planets, Radial velocity, Transit photometry, Astronomy, QB1-991
Abstract: We report the discovery and orbital characterization of three new transiting warm giant planets. These systems were initially identified as presenting single-transit events in the light curves generated from the full-frame images of the Transiting Exoplanet Survey Satellite. Follow-up radial velocity measurements and additional light curves were used to determine the orbital periods and confirm the planetary nature of the candidates. The planets orbit slightly metal-rich late F- and early G-type stars. We find that TOI 4406b has a mass of M _P = 0.30 ± 0.04 M _J , a radius of R _P = 1.00 ± 0.02 R _J , and a low-eccentricity orbit ( e = 0.15 ± 0.05) with a period of P = 30.08364 ±0.00005 days. TOI 2338b has a mass of M _P = 5.98 ± 0.20 M _J , a radius of R _P = 1.00 ± 0.01 R _J , and a highly eccentric orbit ( e = 0.676 ± 0.002) with a period of P = 22.65398 ± 0.00002 days. Finally, TOI 2589b has a mass of M _P = 3.50 ± 0.10 M _J , a radius of R _P = 1.08 ± 0.03 R _J , and an eccentric orbit ( e = 0.522 ± 0.006) with a period of P = 61.6277 ± 0.0002 days. TOI 4406b and TOI 2338b are enriched in metals compared to their host stars, while the structure of TOI 2589b is consistent with having similar metal enrichment to its host star.
Published: 2023
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12. Joint Modelling of Dust Scattering and Thermal Emission: The Spider Complex

Author: Jielai Zhang, Peter G. Martin, Ryan Cloutier, Natalie Price-Jones, Roberto Abraham, Pieter van Dokkum, and Allison Merritt
Subjects: Interstellar dust, Interstellar medium, Astronomical techniques, Submillimeter astronomy, Optical astronomy, Interstellar scattering, Astrophysics, QB460-466
Abstract: Observations across the electromagnetic spectrum of radiative processes involving interstellar dust—emission, absorption, and scattering—are used to constrain the parameters of dust models and more directly to aid in foreground removal of dust for extragalactic and cosmological observations. Dust models can benefit from more independent constraints from complementary observations. Here, we quantify the relationship between scattered light and thermal emission from dust in a diffuse (cirrus) intermediate-latitude cloud, Spider, using data from the Dragonfly Telephoto Array and the Herschel Space Observatory. A challenge for optical observations of faint diffuse cirrus is accurate removal of a contaminating, spatially varying sky. We present a technique to analyze two images of the same cirrus field concurrently, correlating pixel values to capture the relationship and simultaneously fitting the sky-related signal as a complex noncorrelating additive component. For the Spider, we measure a color g − r = 0.644 ± 0.024 and ratios of visible-wavelength to 250 μ m intensity of γ _g _,250 = (0.855 ± 0.025) × 10 ^−3 and γ _r _,250 = (1.55 ± 0.08) × 10 ^−3 for the g and r- bands, respectively. We show how to use any dust model that matches the thermal dust emission to predict an upper limit to the amount of scattered light. The actual brightness of the cirrus will be fainter than this limit because of anisotropic scattering by the dust combined with anisotropy of the incident interstellar radiation field (ISRF). Using models of dust and the ISRF in the literature, we illustrate that the predicted brightness is indeed lower, though not as faint as the observations indicate.
Published: 2023
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13. Independent Validation of the Temperate Super-Earth HD 79211 b using HARPS-N

Author: Victoria DiTomasso, Chantanelle Nava, Mercedes López-Morales, Allyson Bieryla, Ryan Cloutier, Luca Malavolta, Annelies Mortier, Lars A. Buchhave, Keivan G. Stassun, Alessandro Sozzetti, Aldo Stefano Bonomo, David Charbonneau, Andrew Collier Cameron, Rosario Cosentino, Mario Damasso, Xavier Dumusque, A. F. Martínez Fiorenzano, Adriano Ghedina, Avet Harutyunyan, R. D. Haywood, David Latham, Emilio Molinari, Francesco A. Pepe, Matteo Pinamonti, Ennio Poretti, Ken Rice, Dimitar Sasselov, Manu Stalport, Stéphane Udry, Christopher Watson, and Thomas G. Wilson
Subjects: Exoplanet detection methods, Radial velocity, M dwarf stars, Binary stars, Astronomy, QB1-991
Abstract: We present high-precision radial velocities (RVs) from the HARPS-N spectrograph for HD 79210 and HD 79211, two M0V members of a gravitationally bound binary system. We detect a planet candidate with a period of ${24.421}_{-0.017}^{+0.016}$ days around HD 79211 in these HARPS-N RVs, validating the planet candidate originally identified in CARMENES RV data alone. Using HARPS-N, CARMENES, and RVs spanning a total of 25 yr, we further refine the planet candidate parameters to P = 24.422 ± 0.014 days, K = 3.19 ± 0.27 m s ^−1 , M sin i = 10.6 ± 1.2 M _⊕ , and a = 0.142 ± 0.005 au. We do not find any additional planet candidate signals in the data of HD 79211, nor do we find any planet candidate signals in HD 79210. This system adds to the number of exoplanets detected in binaries with M-dwarf members and serves as a case study for planet formation in stellar binaries.
Published: 2023
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14. TOI-1695 b: A Water World Orbiting an Early-M Dwarf in the Planet Radius Valley

Author: Collin Cherubim, Ryan Cloutier, David Charbonneau, Chris Stockdale, Keivan G. Stassun, Richard P. Schwarz, Boris Safonov, Annelies Mortier, Pablo Lewin, David W. Latham, Keith Horne, Raphaëlle D. Haywood, Erica Gonzales, Maria V. Goliguzova, Karen A. Collins, David R. Ciardi, Allyson Bieryla, Alexandre A. Belinski, Bill Wohler, Christopher A. Watson, Roland Vanderspek, Stéphane Udry, Alessandro Sozzetti, Damien Ségransan, Dimitar Sasselov, George R. Ricker, Ken Rice, Ennio Poretti, Giampaolo Piotto, Francesco Pepe, Emilio Molinari, Giuseppina Micela, Michel Mayor, Christophe Lovis, Mercedes López-Morales, Jon M. Jenkins, Zahra Essack, Xavier Dumusque, John P. Doty, Knicole D. Colón, Andrew Collier Cameron, and Lars A. Buchhave
Subjects: Exoplanets, Exoplanet formation, Planet formation, Exoplanet evolution, M dwarf stars, Exoplanet atmospheric evolution, Astronomy, QB1-991
Abstract: Characterizing the bulk compositions of transiting exoplanets within the M dwarf radius valley offers a unique means to establish whether the radius valley emerges from an atmospheric mass-loss process or is imprinted by planet formation itself. We present the confirmation of such a planet orbiting an early-M dwarf ( T _mag = 11.0294 ± 0.0074, M _s = 0.513 ± 0.012 M _⊙ , R _s = 0.515 ± 0.015 R _⊙ , and T _eff = 3690 ± 50 K): TOI-1695 b ( P = 3.13 days and ${R}_{p}={1.90}_{-0.14}^{+0.16}\ {R}_{\oplus }$ ). TOI-1695 b’s radius and orbital period situate the planet between model predictions from thermally driven mass loss versus gas depleted formation, offering an important test case for radius valley emergence models around early-M dwarfs. We confirm the planetary nature of TOI-1695 b based on five sectors of TESS data and a suite of follow-up observations including 49 precise radial velocity measurements taken with the HARPS-N spectrograph. We measure a planetary mass of 6.36 ± 1.00 M _⊕ , which reveals that TOI-1695 b is inconsistent with a purely terrestrial composition of iron and magnesium silicate, and instead is likely a water-rich planet. Our finding that TOI-1695 b is not terrestrial is inconsistent with the planetary system being sculpted by thermally driven mass loss. We present a statistical analysis of seven well-characterized planets within the M dwarf radius valley demonstrating that a thermally driven mass-loss scenario is unlikely to explain this population.
Published: 2023
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15. TOI 560: Two Transiting Planets Orbiting a K Dwarf Validated with iSHELL, PFS, and HIRES RVs

Author: Mohammed El Mufti, Peter P. Plavchan, Howard Isaacson, Bryson L. Cale, Dax L. Feliz, Michael A. Reefe, Coel Hellier, Keivan Stassun, Jason Eastman, Alex Polanski, Ian J. M. Crossfield, Eric Gaidos, Veselin Kostov, Justin M. Wittrock, Joel Villaseñor, Joshua E. Schlieder, Luke G. Bouma, Kevin I. Collins, Farzaneh Zohrabi, Rena A. Lee, Ahmad Sohani, John Berberian, David Vermilion, Patrick Newman, Claire Geneser, Angelle Tanner, Natalie M. Batalha, Courtney Dressing, Benjamin Fulton, Andrew W. Howard, Daniel Huber, Stephen R. Kane, Erik A. Petigura, Paul Robertson, Arpita Roy, Lauren M. Weiss, Aida Behmard, Corey Beard, Ashley Chontos, Fei Dai, Paul A. Dalba, Tara Fetherolf, Steven Giacalone, Michelle L. Hill, Lea A. Hirsch, Rae Holcomb, Jack Lubin, Andrew Mayo, Teo Močnik, Joseph M. Akana Murphy, Lee J. Rosenthal, Ryan A. Rubenzahl, Nicholas Scarsdale, Christopher Stockdale, Karen Collins, Ryan Cloutier, Howard Relles, Thiam-Guan Tan, Nicholas J Scott, Zach Hartman, Elisabeth Matthews, David R. Ciardi, Erica Gonzales, Rachel A. Matson, Charles Beichman, Allyson Bieryla, E. Furlan, Crystal L. Gnilka, Steve B. Howell, Carl Ziegler, César Briceño, Nicholas Law, Andrew W. Mann, Markus Rabus, Marshall C. Johnson, Jessie Christiansen, Laura Kreidberg, David Anthony Berardo, Drake Deming, Varoujan Gorjian, Farisa Y. Morales, Björn Benneke, Diana Dragomir, Robert A. Wittenmyer, Sarah Ballard, Brendan P. Bowler, Jonathan Horner, John Kielkopf, Huigen Liu, Avi Shporer, C. G. Tinney, Hui Zhang, Duncan J. Wright, Brett C. Addison, Matthew W. Mengel, and Jack Okumura
Subjects: Radial velocity, Astronomy, QB1-991
Abstract: We validate the presence of a two-planet system orbiting the 0.15–1.4 Gyr K4 dwarf TOI 560 (HD 73583). The system consists of an inner moderately eccentric transiting mini-Neptune (TOI 560 b, $P={6.3980661}_{-0.0000097}^{+0.0000095}$ days, $e={0.294}_{-0.062}^{+0.13}$ , $M={0.94}_{-0.23}^{+0.31}{M}_{\mathrm{Nep}}$ ) initially discovered in the Sector 8 Transiting Exoplanet Survey Satellite (TESS) mission observations, and a transiting mini-Neptune (TOI 560 c, $P={18.8805}_{-0.0011}^{+0.0024}$ days, $M={1.32}_{-0.32}^{+0.29}{M}_{\mathrm{Nep}}$ ) discovered in the Sector 34 observations, in a rare near-1:3 orbital resonance. We utilize photometric data from TESS Spitzer, and ground-based follow-up observations to confirm the ephemerides and period of the transiting planets, vet false-positive scenarios, and detect the photoeccentric effect for TOI 560 b. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with the iSHELL spectrograph at the NASA Infrared Telescope Facility and the HIRES Spectrograph at Keck Observatory to validate the planetary nature of these signals, which we combine with published Planet Finder Spectrograph RVs from the Magellan Observatory. We detect the masses of both planets at >3 σ significance. We apply a Gaussian process (GP) model to the TESS light curves to place priors on a chromatic RV GP model to constrain the stellar activity of the TOI 560 host star, and confirm a strong wavelength dependence for the stellar activity demonstrating the ability of near-IR RVs to mitigate stellar activity for young K dwarfs. TOI 560 is a nearby moderately young multiplanet system with two planets suitable for atmospheric characterization with the James Webb Space Telescope and other upcoming missions. In particular, it will undergo six transit pairs separated by
Published: 2022
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16. A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterized with CHEOPS

Author: Thomas G Wilson, Elisa Goffo, Yann Alibert, Davide Gandolfi, Andrea Bonfanti, Carina M Persson, Andrew Collier Cameron, Malcolm Fridlund, Luca Fossati, Judith Korth, Willy Benz, Adrien Deline, Hans-Gustav Florén, Pascal Guterman, Vardan Adibekyan, Matthew J Hooton, Sergio Hoyer, Adrien Leleu, Alexander James Mustill, Sébastien Salmon, Sérgio G Sousa, Olga Suarez, Lyu Abe, Abdelkrim Agabi, Roi Alonso, Guillem Anglada, Joel Asquier, Tamas Bárczy, David Barrado Navascues, Susana C C Barros, Wolfgang Baumjohann, Mathias Beck, Thomas Beck, Nicolas Billot, Xavier Bonfils, Alexis Brandeker, Christopher Broeg, Edward M Bryant, Matthew R Burleigh, Marco Buttu, Juan Cabrera, Sébastien Charnoz, David R Ciardi, Ryan Cloutier, William D Cochran, Karen A Collins, Knicole D Colón, Nicolas Crouzet, Szilard Csizmadia, Melvyn B Davies, Magali Deleuil, Laetitia Delrez, Olivier Demangeon, Brice-Olivier Demory, Diana Dragomir, Georgina Dransfield, David Ehrenreich, Anders Erikson, Andrea Fortier, Tianjun Gan, Samuel Gill, Michaël Gillon, Crystal L Gnilka, Nolan Grieves, Sascha Grziwa, Manuel Güdel, Tristan Guillot, Jonas Haldemann, Kevin Heng, Keith Horne, Steve B Howell, Kate G Isaak, Jon M Jenkins, Eric L N Jensen, Laszlo Kiss, Gaia Lacedelli, Kristine Lam, Jacques Laskar, David W Latham, Alain Lecavelier des Etangs, Monika Lendl, Kathryn V Lester, Alan M Levine, John Livingston, Christophe Lovis, Rafael Luque, Demetrio Magrin, Wenceslas Marie-Sainte, Pierre F L Maxted, Andrew W Mayo, Brian McLean, Marko Mecina, Djamel Mékarnia, Valerio Nascimbeni, Louise D Nielsen, Göran Olofsson, Hugh P Osborn, Hannah L M Osborne, Roland Ottensamer, Isabella Pagano, Enric Pallé, Gisbert Peter, Giampaolo Piotto, Don Pollacco, Didier Queloz, Roberto Ragazzoni, Nicola Rando, Heike Rauer, Seth Redfield, Ignasi Ribas, George R Ricker, Martin Rieder, Nuno C Santos, Gaetano Scandariato, François-Xavier Schmider, Richard P Schwarz, Nicholas J Scott, Sara Seager, Damien Ségransan, Luisa Maria Serrano, Attila E Simon, Alexis M S Smith, Manfred Steller, Chris Stockdale, Gyula Szabó, Nicolas Thomas, Eric B Ting, Amaury H M J Triaud, Stéphane Udry, Vincent Van Eylen, Valérie Van Grootel, Roland K Vanderspek, Valentina Viotto, Nicholas Walton, and Joshua N Winn
Published: 2022
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17. TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet

Author: Ares Osborn, David J Armstrong, Bryson Cale, Rafael Brahm, Robert A Wittenmyer, Fei Dai, Ian J M Crossfield, Edward M Bryant, Vardan Adibekyan, Ryan Cloutier, Karen A Collins, E Delgado Mena, Malcolm Fridlund, Coel Hellier, Steve B Howell, George W King, Jorge Lillo-Box, Jon Otegi, S Sousa, Keivan G Stassun, Elisabeth C Matthews, Carl Ziegler, George Ricker, Roland Vanderspek, David W Latham, S Seager, Joshua N Winn, Jon M Jenkins, Jack S Acton, Brett C Addison, David R Anderson, Sarah Ballard, David Barrado, Susana C C Barros, Natalie Batalha, Daniel Bayliss, Thomas Barclay, Björn Benneke, John Berberian, Francois Bouchy, Brendan P Bowler, César Briceño, Christopher J Burke, Matthew R Burleigh, Sarah L Casewell, David Ciardi, Kevin I Collins, Benjamin F Cooke, Olivier D S Demangeon, Rodrigo F Díaz, C Dorn, Diana Dragomir, Courtney Dressing, Xavier Dumusque, Néstor Espinoza, P Figueira, Benjamin Fulton, E Furlan, E Gaidos, C Geneser, Samuel Gill, Michael R Goad, Erica J Gonzales, Varoujan Gorjian, Maximilian N Günther, Ravit Helled, Beth A Henderson, Thomas Henning, Aleisha Hogan, Saeed Hojjatpanah, Jonathan Horner, Andrew W Howard, Sergio Hoyer, Dan Huber, Howard Isaacson, James S Jenkins, Eric L N Jensen, Andrés Jordán, Stephen R Kane, Richard C Kidwell, John Kielkopf, Nicholas Law, Monika Lendl, M Lund, Rachel A Matson, Andrew W Mann, James McCormac, Matthew W Mengel, Farisa Y Morales, Louise D Nielsen, Jack Okumura, Hugh P Osborn, Erik A Petigura, Peter Plavchan, Don Pollacco, Elisa V Quintana, Liam Raynard, Paul Robertson, Mark E Rose, Arpita Roy, Michael Reefe, Alexandre Santerne, Nuno C Santos, Paula Sarkis, J Schlieder, Richard P Schwarz, Nicholas J Scott, Avi Shporer, A M S Smith, C Stibbard, Chris Stockdale, Paul A Strøm, Joseph D Twicken, Thiam-Guan Tan, A Tanner, J Teske, Rosanna H Tilbrook, C G Tinney, Stephane Udry, Jesus Noel Villaseñor, Jose I Vines, Sharon X Wang, Lauren M Weiss, Richard G West, Peter J Wheatley, Duncan J Wright, Hui Zhang, and F Zohrabi
Published: 2021
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18. A temperate Earth-sized planet with tidal heating transiting an M6 star

Author: Merrin S. Peterson, Björn Benneke, Karen Collins, Caroline Piaulet, Ian J. M. Crossfield, Mohamad Ali-Dib, Jessie L. Christiansen, Jonathan Gagné, Jackie Faherty, Edwin Kite, Courtney Dressing, David Charbonneau, Felipe Murgas, Marion Cointepas, Jose Manuel Almenara, Xavier Bonfils, Stephen Kane, Michael W. Werner, Varoujan Gorjian, Pierre-Alexis Roy, Avi Shporer, Francisco J. Pozuelos, Quentin Jay Socia, Ryan Cloutier, Jeremy Dietrich, Jonathan Irwin, Lauren Weiss, William Waalkes, Zach Berta-Thomson, Thomas Evans, Daniel Apai, Hannu Parviainen, Enric Pallé, Norio Narita, Andrew W. Howard, Diana Dragomir, Khalid Barkaoui, Michaël Gillon, Emmanuel Jehin, Elsa Ducrot, Zouhair Benkhaldoun, Akihiko Fukui, Mayuko Mori, Taku Nishiumi, Kiyoe Kawauchi, George Ricker, David W. Latham, Joshua N. Winn, Sara Seager, Howard Isaacson, Alex Bixel, Aidan Gibbs, Jon M. Jenkins, Jeffrey C. Smith, Jose Perez Chavez, Benjamin V. Rackham, Thomas Henning, Paul Gabor, Wen-Ping Chen, Nestor Espinoza, Eric L. N. Jensen, Kevin I. Collins, Richard P. Schwarz, Dennis M. Conti, Gavin Wang, John F. Kielkopf, Shude Mao, Keith Horne, Ramotholo Sefako, Samuel N. Quinn, Dan Moldovan, Michael Fausnaugh, Gábor Fűűrész, and Thomas Barclay
Subjects: Multidisciplinary
Published: 2023

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

Author: Ryan Cloutier, David Charbonneau, Keivan G. Stassun, Felipe Murgas, Annelies Mortier, Robert Massey, Jack J. Lissauer, David W. Latham, Jonathan Irwin, Raphaëlle D. Haywood, Pere Guerra, Eric Girardin, Steven Giacalone, Pau Bosch-Cabot, Allyson Bieryla, Joshua Winn, Christopher A. Watson, Roland Vanderspek, Stéphane Udry, Motohide Tamura, Alessandro Sozzetti, Avi Shporer, Damien Ségransan, Sara Seager, Arjun B. Savel, Dimitar Sasselov, Mark Rose, George Ricker, Ken Rice, Elisa V. Quintana, Samuel N. Quinn, Giampaolo Piotto, David Phillips, Francesco Pepe, Marco Pedani, and Steve B Howell
Subjects: Astrophysics
Published: 2021
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20. The First Habitable-zone Earth-sized Planet from TESS. I. Validation of the TOI-700 System

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

Author: Joseph E. Rodriguez, Andrew Vanderburg, Sebastian Zieba, Laura Kreidberg, Caroline V. Morley, Jason D. Eastman, Stephen R. Kane, Alton Spencer, Samuel N. Quinn, Ryan Cloutier, Chelsea X. Huang, Karen A. Collins, Andrew W. Mann, Emily Gilbert, Joshua E. Schlieder, Elisa V. Quintana, Thomas Barclay, Gabrielle Suissa, Ravi kumar Kopparapu, Courtney D. Dressing, George R. Ricker, Roland K. Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Zachory Berta-Thompson, Patricia T. Boyd, David Charbonneau, Douglas A. Caldwell, Eugene Chiang, Jessie L. Christiansen, David R. Ciardi, Knicole D. Colón, John Doty, Tianjun Gan, Natalia Guerrero, Maximilian N. Günther, Eve J. Lee, Alan M. Levine, Eric Lopez, Philip S. Muirhead, Elisabeth Newton, Mark E. Rose, Joseph D. Twicken, and Jesus Noel Villaseñor
Subjects: Astronomy, Astrophysics
Abstract: We present Spitzer 4.5 μm observations of the transit of TOI-700 d, a habitable-zone Earth-sized planet in a multiplanet system transiting a nearby M-dwarf star (TIC 150428135, 2MASS J06282325–6534456). TOI-700 d has a radius of 1.144 (+0.062, -0.061)Rꚛ and orbits within its host star’s conservative habitable zone with a period of 37.42 days (T(eq)~269 K). TOI-700 also hosts two small inner planets (R(b)=1.037(+0.065, -0.064) Rꚛ and R(c)=2.65(+0.16,-0.15) Rꚛ with periods of 9.98 and 16.05 days, respectively. Our Spitzer observations confirm the Transiting Exoplanet Survey Satellite (TESS) detection of TOI-700 d and remove any remaining doubt that it is a genuine planet. We analyze the Spitzer light curve combined with the 11 sectors of TESS observations and a transit of TOI-700 c from the LCOGT network to determine the full system parameters. Although studying the atmosphere of TOI-700 d is not likely feasible with upcoming facilities, it may be possible to measure the mass of TOI-700 d using state-of-the-art radial velocity (RV) instruments (expected RV semiamplitude of ∼70 cm/s).
Published: 2020
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22. TOI-1235 b: A Keystone Super-Earth for Testing Radius Valley Emergence Models around Early M Dwarfs

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

Author: Paul A. Dalba, Arvind F. Gupta, Joseph E. Rodriguez, Diana Dragomir, Chelsea X. Huang, Stephen R. Kane, Samuel N. Quinn, Allyson Bieryla, Gilbert A. Esquerdo, Benjamin J. Fulton, Nicholas Scarsdale, Natalie M. Batalha, Corey Beard, Aida Behmard, Ashley Chontos, Ian J. M. Crossfield, Courtney D. Dressing, Steven Giacalone, Michelle L. Hill, Lea A. Hirsch, Andrew W. Howard, Daniel Huber, Howard Isaacson, Molly Kosiarek, Jack Lubin, Andrew W. Mayo, Teo Mocnik, Joseph M. Akana Murphy, Erik A. Petigura, Paul Robertson, Lee J. Rosenthal, Arpita Roy, Ryan A. Rubenzahl, Judah Van Zandt, Lauren M. Weiss, Emil Knudstrup, Mads F. Andersen, Frank Grundahl, Xinyu Yao, Joshua Pepper, Steven Villanueva Jr, David R. Ciardi, Ryan Cloutier, Thomas Lee Jacobs, Martti H. Kristiansen, Daryll M. LaCourse, Monika Lendl, Hugh P. Osborn, Enric Palle, Keivan G. Stassun, Daniel J. Stevens, George R. Ricker, Roland Vanderspek, David W. Latham, S. Seager, Joshua N. Winn, Jon M. Jenkins, Douglas A. Caldwell, Tansu Daylan, William Fong, Robert F. Goeke, Mark E. Rose, Pamela Rowden, Joshua E. Schlieder, Jeffrey C. Smith, and Andrew Vanderburg
Subjects: Astronomy, Astrophysics
Abstract: We report the detection of a Saturn-size exoplanet orbiting HD 332231 (TOI 1456) in light curves from the Transiting Exoplanet Survey Satellite (TESS). HD 332231—an F8 dwarf star with a V-band magnitude of 8.56—was observed by TESS in Sectors 14 and 15. We detect a single-transit event in the Sector 15 presearch data conditioning (PDC) light curve. We obtain spectroscopic follow-up observations of HD 332231 with the Automated Planet Finder, Keck I, and SONG telescopes. The orbital period we infer from radial velocity (RV) observations leads to the discovery of another transit in Sector 14 that was masked by PDC due to scattered light contamination. A joint analysis of the transit and RV data confirms the planetary nature of HD 332231 b, a Saturn-size (0.867 (+0.027,-0.025 R(J)), sub-Saturn-mass (0.244 ± 0.021M(J)) exoplanet on a 18.71 day circular orbit. The low surface gravity of HD 332231 b and the relatively low stellar flux it receives make it a compelling target for transmission spectroscopy. Also, the stellar obliquity is likely measurable via the Rossiter–McLaughlin effect, an exciting prospect given the 0.14 au orbital separation of HD 332231 b. The spectroscopic observations do not provide substantial evidence for any additional planets in the HD 332231 system, but continued RV monitoring is needed to further characterize this system. We also predict that the frequency and duration of masked data in the PDC light curves for TESS Sectors 14–16 could hide transits of some exoplanets with orbital periods between 10.5 and 17.5 days.
Published: 2020
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24. GJ 1252 b: A 1.2 R⊕ Planet Transiting an M3 Dwarf at 20.4 pc

Author: Avi Shporer, Karen A. Collins, Nicola Astudillo-Defru, Jonathan Irwin, Xavier Bonfils, Kevin I. Collins, Elisabeth Matthews, Jennifer G. Winters, David R. Anderson, James D. Armstrong, David Charbonneau, Ryan Cloutier, Tansu Daylan, Tianjun Gan, Maximilian N. Günther, Coel Hellier, Keith Horne, Chelsea X. Huang, Eric L. N. Jensen, John Kielkopf, Enric Palle, Ramotholo Sefako, Keivan G. Stassun, Thiam-Guan Tan, Andrew Vanderburg, George R. Ricker, David W. Latham, Roland Vanderspek, Sara Seager, Joshua N. Winn, Jon M Jenkins, Knicole Colon, Courtney Dressing, Sébastien Léepine, Philip S. Muirhead, Mark E. Rose, Joseph D Twicken, and Jesus Noel Villasenor
Subjects: Astronomy, Astrophysics
Abstract: We report the discovery of GJ 1252 b, a planet with a radius of 1.193 ± 0.074 R⊕ and an orbital period of 0.52 days around an M3-type star (0.381 ± 0.019 M⊕, 0.391 ± 0.020 R⊕) located 20.385 ± 0.019 pc away. We use Transiting Exoplanet Survey Satellite (TESS) data, ground-based photometry and spectroscopy, Gaia astrometry, and high angular resolution imaging to show that the transit signal seen in the TESS data must originate from a transiting planet. We do so by ruling out all false-positive scenarios that attempt to explain the transit signal as originating from an eclipsing stellar binary. Precise Doppler monitoring also leads to a tentative mass measurement of 2.09 ± 0.56 M⊕. The host star proximity, brightness (V = 12.19 mag, K = 7.92 mag), low stellar activity, and the system's short orbital period make this planet an attractive target for detailed characterization, including precise mass measurement, looking for other objects in the system, and planet atmosphere characterization.
Published: 2020
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25. Validation of 13 Hot and Potentially Terrestrial TESS Planets

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

Author: Nicholas Saunders, Samuel K. Grunblatt, Daniel Huber, Karen A. Collins, Eric L. N. Jensen, Andrew Vanderburg, Rafael Brahm, Andrés Jordán, Néstor Espinoza, Thomas Henning, Melissa J. Hobson, Samuel N. Quinn, George Zhou, R. Paul Butler, Lisa Crause, Rudi B. Kuhn, K. Moses Mogotsi, Coel Hellier, Ruth Angus, Soichiro Hattori, Ashley Chontos, George R. Ricker, Jon M. Jenkins, Peter Tenenbaum, David W. Latham, Sara Seager, Roland K. Vanderspek, Joshua N. Winn, Chris Stockdale, and Ryan Cloutier
Published: 2022
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27. CO or no CO? Narrowing the CO abundance constraint and recovering the H2O detection in the atmosphere of WASP-127 b using SPIRou

Author: Anne Boucher, David Lafreniére, Stefan Pelletier, Antoine Darveau-Bernier, Michael Radica, Romain Allart, Étienne Artigau, Neil J Cook, Florian Debras, René Doyon, Eric Gaidos, Björn Benneke, Charles Cadieux, Andres Carmona, Ryan Cloutier, Pía Cortés-Zuleta, Nicolas B Cowan, Xavier Delfosse, Jean-François Donati, Pascal Fouqué, Thierry Forveille, Konstantin Grankin, Guillaume Hébrard, Jorge H C Martins, Eder Martioli, Adrien Masson, and Sandrine Vinatier
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: Precise measurements of chemical abundances in planetary atmospheres are necessary to constrain the formation histories of exoplanets. A recent study of WASP-127b, a close-in puffy sub-Saturn orbiting its solar-type host star in 4.2 d, using HST and Spitzer revealed a feature-rich transmission spectrum with strong excess absorption at 4.5 um. However, the limited spectral resolution and coverage of these instruments could not distinguish between CO and/or CO2 absorption causing this signal, with both low and high C/O ratio scenarios being possible. Here we present near-infrared (0.9--2.5 um) transit observations of WASP-127 b using the high-resolution SPIRou spectrograph, with the goal to disentangle CO from CO2 through the 2.3 um CO band. With SPIRou, we detect H2O at a t-test significance of 5.3 sigma and observe a tentative (3 sigma) signal consistent with OH absorption. From a joint SPIRou + HST + Spitzer retrieval analysis, we rule out a CO-rich scenario by placing an upper limit on the CO abundance of log10[CO], 23 pages, 13 figures, Submitted for publication in the Monthly Notice of the Royal Astronomical Society
Published: 2023

28. The Magellan-TESS Survey. I. Survey Description and Midsurvey Results* †

Author: Johanna Teske, Sharon Xuesong Wang, Angie Wolfgang, Tianjun Gan, Mykhaylo Plotnykov, David J. Armstrong, R. Paul Butler, Bryson Cale, Jeffrey D. Crane, Ward Howard, Eric L. N. Jensen, Nicholas Law, Stephen A. Shectman, Peter Plavchan, Diana Valencia, Andrew Vanderburg, George R. Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Vardan Adibekyan, David Barrado, Susana C. C. Barros, Zouhair Benkhaldoun, David J. A. Brown, Edward M. Bryant, Jennifer Burt, Douglas A. Caldwell, David Charbonneau, Ryan Cloutier, Karen A. Collins, Kevin I. Collins, Knicole D. Colon, Dennis M. Conti, Olivier D. S. Demangeon, Jason D. Eastman, Mohammed Elmufti, Fabo Feng, Erin Flowers, Natalia M. Guerrero, Saeed Hojjatpanah, Jonathan M. Irwin, Giovanni Isopi, Jorge Lillo-Box, Franco Mallia, Bob Massey, Mayuko Mori, Susan E. Mullally, Norio Narita, Taku Nishiumi, Ares Osborn, Martin Paegert, Jerome Pitogo de Leon, Samuel N. Quinn, Michael Reefe, Richard P. Schwarz, Avi Shporer, Abderahmane Soubkiou, Sérgio G. Sousa, Chris Stockdale, Paul A. Strøm, Thiam-Guan Tan, Jiaxin Tang, Peter Tenenbaum, Peter J. Wheatley, Justin Wittrock, Daniel A. Yahalomi, and Farzaneh Zohrabi
Published: 2021
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29. TESS Hunt for Young and Maturing Exoplanets (THYME). IV. Three Small Planets Orbiting a 120 Myr Old Star in the Pisces–Eridanus Stream*

Author: Elisabeth R. Newton, Andrew W. Mann, Adam L. Kraus, John H. Livingston, Andrew Vanderburg, Jason L. Curtis, Pa Chia Thao, Keith Hawkins, Mackenna L. Wood, Aaron C. Rizzuto, Abderahmane Soubkiou, Benjamin M. Tofflemire, George Zhou, Ian J. M. Crossfield, Logan A. Pearce, Karen A. Collins, Dennis M. Conti, Thiam-Guan Tan, Steven Villeneuva, Alton Spencer, Diana Dragomir, Samuel N. Quinn, Eric L. N. Jensen, Kevin I. Collins, Chris Stockdale, Ryan Cloutier, Coel Hellier, Zouhair Benkhaldoun, Carl Ziegler, César Briceño, Nicholas Law, Björn Benneke, Jessie L. Christiansen, Varoujan Gorjian, Stephen R. Kane, Laura Kreidberg, Farisa Y. Morales, Michael W Werner, Joseph D. Twicken, Alan M. Levine, David R. Ciardi, Natalia M. Guerrero, Katharine Hesse, Elisa V. Quintana, Bernie Shiao, Jeffrey C. Smith, Guillermo Torres, George R. Ricker, Roland Vanderspek, Sara Seager, Joshua N. Winn, Jon M. Jenkins, and David W. Latham
Published: 2021
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30. TOI-1695 b: A Water World Orbiting an Early M Dwarf in the Planet Radius Valley

Author: Collin Cherubim, Ryan Cloutier, David Charbonneau, Chris Stockdale, Keivan G. Stassun, Richard P. Schwarz, Boris Safonov, Annelies Mortier, Pablo Lewin, David W. Latham, Keith Horne, Raphaëlle D. Haywood, Erica Gonzales, Maria V. Goliguzova, Karen A. Collins, David R. Ciardi, Allyson Bieryla, Alexandre A. Belinski, Bill Wohler, Christopher A. Watson, Roland Vanderspek, Stéphane Udry, Alessandro Sozzetti, Damien Ségransan, Dimitar Sasselov, George R. Ricker, Ken Rice, Ennio Poretti, Giampaolo Piotto, Francesco Pepe, Emilio Molinari, Giuseppina Micela, Michel Mayor, Christophe Lovis, Mercedes López-Morales, Jon M. Jenkins, Zahra Essack, Xavier Dumusque, John P. Doty, Knicole D. Colón, Andrew Collier Cameron, Lars A. Buchhave, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Cherubim, Collin [0000-0002-8466-5469], Cloutier, Ryan [0000-0001-5383-9393], Charbonneau, David [0000-0002-9003-484X], Stockdale, Chris [0000-0003-2163-1437], Stassun, Keivan G [0000-0002-3481-9052], Schwarz, Richard P [0000-0001-8227-1020], Safonov, Boris [0000-0003-1713-3208], Mortier, Annelies [0000-0001-7254-4363], Lewin, Pablo [0000-0003-0828-6368], Latham, David W [0000-0001-9911-7388], Horne, Keith [0000-0003-1728-0304], Haywood, Raphaëlle D [0000-0001-9140-3574], Collins, Karen A [0000-0001-6588-9574], Ciardi, David R [0000-0002-5741-3047], Bieryla, Allyson [0000-0001-6637-5401], Belinski, Alexandre A [0000-0003-3469-0989], Wohler, Bill [0000-0002-5402-9613], Watson, Christopher A [0000-0002-9718-3266], Vanderspek, Roland [0000-0001-6763-6562], Udry, Stéphane [0000-0001-7576-6236], Sozzetti, Alessandro [0000-0002-7504-365X], Ségransan, Damien [0000-0003-2355-8034], Sasselov, Dimitar [0000-0001-7014-1771], Ricker, George R [0000-0003-2058-6662], Rice, Ken [0000-0002-6379-9185], Poretti, Ennio [0000-0003-1200-0473], Piotto, Giampaolo [0000-0002-9937-6387], Molinari, Emilio [0000-0002-1742-7735], Micela, Giuseppina [0000-0002-9900-4751], Mayor, Michel [0000-0002-9352-5935], López-Morales, Mercedes [0000-0003-3204-8183], Jenkins, Jon M [0000-0002-4715-9460], Essack, Zahra [0000-0002-2482-0180], Dumusque, Xavier [0000-0002-9332-2011], Doty, John P [0000-0003-2996-8421], Colón, Knicole D [0000-0001-8020-7121], Cameron, Andrew Collier [0000-0002-8863-7828], Buchhave, Lars A [0000-0003-1605-5666], and Apollo - University of Cambridge Repository
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), MCC, Space and Planetary Science, The Solar System, Exoplanets, and Astrobiology, FOS: Physical sciences, QB Astronomy, Astronomy and Astrophysics, 5109 Space Sciences, 3rd-DAS, 51 Physical Sciences, QB, Astrophysics - Earth and Planetary Astrophysics
Abstract: Characterizing the bulk compositions of transiting exoplanets within the M dwarf radius valley offers a unique means to establish whether the radius valley emerges from an atmospheric mass loss process or is imprinted by planet formation itself. We present the confirmation of such a planet orbiting an early M dwarf ($T_{\rm mag} = 11.0294 \pm 0.0074, M_s = 0.513 \pm 0.012\ M_\odot, R_s = 0.515 \pm 0.015\ R_\odot, T_{\rm eff} =3690\pm 50 K$): TOI-1695 b ($P = 3.13$ days, $R_p = 1.90^{+0.16}_{-0.14}\ R_\oplus$). TOI-1695 b's radius and orbital period situate the planet between model predictions from thermally-driven mass loss versus gas depleted formation, offering an important test case for radius valley emergence models around early M dwarfs. We confirm the planetary nature of TOI-1695 b based on five sectors of TESS data and a suite of follow-up observations including 49 precise radial velocity measurements taken with the HARPS-N spectrograph. We measure a planetary mass of $6.36 \pm 1.00\ M_\oplus$, which reveals that TOI-1695 b is inconsistent with a purely terrestrial composition of iron and magnesium silicate, and instead is likely a water-rich planet. Our finding that TOI-1695 b is not terrestrial is inconsistent with the planetary system being sculpted by thermally driven mass loss. We present a statistical analysis of seven well-characterized planets within the M dwarf radius valley demonstrating that a thermally-driven mass loss scenario is unlikely to explain this population., 22 pages, 11 figures. Accepted in AJ
Published: 2022

31. A Second Planet Transiting LTT 1445A and a Determination of the Masses of Both Worlds

Author: Jennifer G. Winters, Ryan Cloutier, Amber A. Medina, Jonathan M. Irwin, David Charbonneau, Nicola Astudillo-Defru, Xavier Bonfils, Andrew W. Howard, Howard Isaacson, Jacob L. Bean, Andreas Seifahrt, Johanna K. Teske, Jason D. Eastman, Joseph D. Twicken, Karen A. Collins, Eric L. N. Jensen, Samuel N. Quinn, Matthew J. Payne, Martti H. Kristiansen, Alton Spencer, Andrew Vanderburg, Mathias Zechmeister, Lauren M. Weiss, Sharon Xuesong Wang, Gavin Wang, Stéphane Udry, Ivan A. Terentev, Julian Stürmer, Gudmundur Stefánsson, Avi Shporer, Stephen Shectman, Ramotholo Sefako, Hans Martin Schwengeler, Richard P. Schwarz, Nicholas Scarsdale, Ryan A. Rubenzahl, Arpita Roy, Lee J. Rosenthal, Paul Robertson, Erik A. Petigura, Francesco Pepe, Mark Omohundro, Joseph M. Akana Murphy, Felipe Murgas, Teo Močnik, Benjamin T. Montet, Ronald Mennickent, Andrew W. Mayo, Bob Massey, Jack Lubin, Christophe Lovis, Pablo Lewin, David Kasper, Stephen R. Kane, Jon M. Jenkins, Daniel Huber, Keith Horne, Michelle L. Hill, Paula Gorrini, Steven Giacalone, Benjamin Fulton, Thierry Forveille, Pedro Figueira, Tara Fetherolf, Courtney Dressing, Rodrigo F. Díaz, Xavier Delfosse, Paul A. Dalba, Fei Dai, C. C. Cortés, Ian J. M. Crossfield, Jeffrey D. Crane, Dennis M. Conti, Kevin I. Collins, Ashley Chontos, R. Paul Butler, Peyton Brown, Madison Brady, Aida Behmard, Corey Beard, Natalie M. Batalha, Jose-Manuel Almenara, Université du Québec à Rimouski (UQAR), Departamento de Matemática y Fı́sica Aplicadas [Concepcion] (DMFA), Universidad Católica de la Santísima Concepción (UCSC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
Subjects: STELLAR ACTIVITY, FOS: Physical sciences, SUPER-EARTH, Astrophysics::Cosmology and Extragalactic Astrophysics, EARTH-SIZED PLANET, HARPS, NEARBY, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, QC, TERRESTRIAL PLANET, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QB, MCC, Earth and Planetary Astrophysics (astro-ph.EP), RADIAL-VELOCITIES, ERROR-CORRECTION, M DWARFS, Astronomy and Astrophysics, 3rd-DAS, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], SYSTEM, Astrophysics - Earth and Planetary Astrophysics
Abstract: LTT 1445 is a hierarchical triple M-dwarf star system located at a distance of 6.86 parsecs. The primary star LTT 1445A (0.257 M_Sun) is known to host the transiting planet LTT 1445Ab with an orbital period of 5.4 days, making it the second closest known transiting exoplanet system, and the closest one for which the host is an M dwarf. Using TESS data, we present the discovery of a second planet in the LTT 1445 system, with an orbital period of 3.1 days. We combine radial velocity measurements obtained from the five spectrographs ESPRESSO, HARPS, HIRES, MAROON-X, and PFS to establish that the new world also orbits LTT 1445A. We determine the mass and radius of LTT 1445Ab to be 2.87+/-0.25 M_Earth and 1.304^{+0.067}_{-0.060} R_Earth, consistent with an Earth-like composition. For the newly discovered LTT 1445Ac, we measure a mass of 1.54^{+0.20}_{-0.19} M_Earth and a minimum radius of 1.15 R_Earth, but we cannot determine the radius directly as the signal-to-noise of our light curve permits both grazing and non-grazing configurations. Using MEarth photometry and ground-based spectroscopy, we establish that star C (0.161 M_Sun) is likely the source of the 1.4-day rotation period, and star B (0.215 M_Sun) has a likely rotation period of 6.7 days. We estimate a probable rotation period of 85 days for LTT 1445A. Thus, this triple M-dwarf system appears to be in a special evolutionary stage where the most massive M dwarf has spun down, the intermediate mass M dwarf is in the process of spinning down, while the least massive stellar component has not yet begun to spin down., Comment: Accepted to the Astronomical Journal. 4 tables, 10 figures; RV table available upon request
Published: 2022

32. The LHS 1678 system : two earth-sized transiting planets and an astrometric companion orbiting an M dwarf near the convective boundary at 20 pc

Author: Michele L. Silverstein, Joshua E. Schlieder, Thomas Barclay, Benjamin J. Hord, Wei-Chun Jao, Eliot Halley Vrijmoet, Todd J. Henry, Ryan Cloutier, Veselin B. Kostov, Ethan Kruse, Jennifer G. Winters, Jonathan M. Irwin, Stephen R. Kane, Keivan G. Stassun, Chelsea Huang, Michelle Kunimoto, Evan Tey, Andrew Vanderburg, Nicola Astudillo-Defru, Xavier Bonfils, C. E. Brasseur, David Charbonneau, David R. Ciardi, Karen A. Collins, Kevin I. Collins, Dennis M. Conti, Ian J. M. Crossfield, Tansu Daylan, John P. Doty, Courtney D. Dressing, Emily A. Gilbert, Keith Horne, Jon M. Jenkins, David W. Latham, Andrew W. Mann, Elisabeth Matthews, Leonardo A. Paredes, Samuel N. Quinn, George R. Ricker, Richard P. Schwarz, Sara Seager, Ramotholo Sefako, Avi Shporer, Jeffrey C. Smith, Christopher Stockdale, Thiam-Guan Tan, Guillermo Torres, Joseph D. Twicken, Roland Vanderspek, Gavin Wang, Joshua N. Winn, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Bonfils, Xavier, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), University of Washington [Seattle], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)
Subjects: FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, M dwarf stars, NCAD, Astrophysics::Solar and Stellar Astrophysics, QB Astronomy, Exoplanet systems, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QC, QB, Earth and Planetary Astrophysics (astro-ph.EP), MCC, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, 3rd-DAS, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Low mass stars, Transit photometry, Astrometric binary stars, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the TESS discovery of the LHS 1678 (TOI-696) exoplanet system, comprised of two approximately Earth-sized transiting planets and a likely astrometric brown dwarf orbiting a bright ($V_J$=12.5, $K_s$=8.3) M2 dwarf at 19.9 pc. The two TESS-detected planets are of radius 0.70$\pm$0.04 $R_\oplus$ and 0.98$\pm$0.06 $R_\oplus$ in 0.86-day and 3.69-day orbits, respectively. Both planets are validated and characterized via ground-based follow-up observations. HARPS RV monitoring yields 97.7 percentile mass upper limits of 0.35 $M_\oplus$ and 1.4 $M_\oplus$ for planets b and c, respectively. The astrometric companion detected by the CTIO/SMARTS 0.9m has an orbital period on the order of decades and is undetected by other means. Additional ground-based observations constrain the companion to being a high-mass brown dwarf or smaller. Each planet is of unique interest; the inner planet has an ultra-short period, and the outer planet is in the Venus zone. Both are promising targets for atmospheric characterization with the JWST and mass measurements via extreme-precision radial velocity. A third planet candidate of radius 0.9$\pm$0.1 $R_\oplus$ in a 4.97-day orbit is also identified in multi-Cycle TESS data for validation in future work. The host star is associated with an observed gap in the lower main sequence of the Hertzsprung-Russell diagram. This gap is tied to the transition from partially- to fully-convective interiors in M dwarfs, and the effect of the associated stellar astrophysics on exoplanet evolution is currently unknown. The culmination of these system properties makes LHS 1678 a unique, compelling playground for comparative exoplanet science and understanding the formation and evolution of small, short-period exoplanets orbiting low-mass stars., Published in The Astronomical Journal (31 pages, 21 figures, 11 tables, 3 appendices)
Published: 2022

33. TOI-1452 b: SPIRou and TESS Reveal a Super-Earth in a Temperate Orbit Transiting an M4 Dwarf

Author: Charles Cadieux, René Doyon, Mykhaylo Plotnykov, Guillaume Hébrard, Farbod Jahandar, Étienne Artigau, Diana Valencia, Neil J. Cook, Eder Martioli, Thomas Vandal, Jean-François Donati, Ryan Cloutier, Norio Narita, Akihiko Fukui, Teruyuki Hirano, François Bouchy, Nicolas B. Cowan, Erica J. Gonzales, David R. Ciardi, Keivan G. Stassun, Luc Arnold, Björn Benneke, Isabelle Boisse, Xavier Bonfils, Andrés Carmona, Pía Cortés-Zuleta, Xavier Delfosse, Thierry Forveille, Pascal Fouqué, João Gomes da Silva, Jon M. Jenkins, Flavien Kiefer, Ágnes Kóspál, David Lafrenière, Jorge H. C. Martins, Claire Moutou, J.-D. do Nascimento, Merwan Ould-Elhkim, Stefan Pelletier, Joseph D. Twicken, Luke G. Bouma, Scott Cartwright, Antoine Darveau-Bernier, Konstantin Grankin, Masahiro Ikoma, Taiki Kagetani, Kiyoe Kawauchi, Takanori Kodama, Takayuki Kotani, David W. Latham, Kristen Menou, George Ricker, Sara Seager, Motohide Tamura, Roland Vanderspek, Noriharu Watanabe, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, and ANR-18-CE31-0019,SPlaSH,Recherche de planètes habitables avec SPIRou(2018)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Exoplanets, FOS: Physical sciences, Astronomy and Astrophysics, M dwarf stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Super Earths, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract: 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
Published: 2022
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34. Transit timings variations in the three-planet system : TOI-270

Author: Laurel Kaye, Shreyas Vissapragada, Maximilian N Günther, Suzanne Aigrain, Thomas Mikal-Evans, Eric L N Jensen, Hannu Parviainen, Francisco J Pozuelos, Lyu Abe, Jack S Acton, Abdelkrim Agabi, Douglas R Alves, David R Anderson, David J Armstrong, Khalid Barkaoui, Oscar Barragán, Björn Benneke, Patricia T Boyd, Rafael Brahm, Ivan Bruni, Edward M Bryant, Matthew R Burleigh, Sarah L Casewell, David Ciardi, Ryan Cloutier, Karen A Collins, Kevin I Collins, Dennis M Conti, Ian J M Crossfield, Nicolas Crouzet, Tansu Daylan, Diana Dragomir, Georgina Dransfield, Daniel Fabrycky, Michael Fausnaugh, Gábor Fuűrész, Tianjun Gan, Samuel Gill, Michaël Gillon, Michael R Goad, Varoujan Gorjian, Michael Greklek-McKeon, Natalia Guerrero, Tristan Guillot, Emmanuël Jehin, J S Jenkins, Monika Lendl, Jacob Kamler, Stephen R Kane, John F Kielkopf, Michelle Kunimoto, Wenceslas Marie-Sainte, James McCormac, Djamel Mékarnia, Farisa Y Morales, Maximiliano Moyano, Enric Palle, Vivien Parmentier, Howard M Relles, François-Xavier Schmider, Richard P Schwarz, S Seager, Alexis M S Smith, Thiam-Guan Tan, Jake Taylor, Amaury H M J Triaud, Joseph D Twicken, Stephane Udry, J I Vines, Gavin Wang, Peter J Wheatley, and Joshua N Winn
Subjects: Space and Planetary Science, planets and satellites: composition, planets and satellites: formation, Astronomy and Astrophysics, planets and satellites: fundamental parameters, QB
Abstract: We present ground- and space-based photometric observations of TOI-270 (L231-32), a system of three transiting planets consisting of one super-Earth and two sub-Neptunes discovered by TESS around a bright (K-mag = 8.25) M3V dwarf. The planets orbit near low-order mean-motion resonances (5:3 and 2:1) and are thus expected to exhibit large transit timing variations (TTVs). Following an extensive observing campaign using eight different observatories between 2018 and 2020, we now report a clear detection of TTVs for planets c and d, with amplitudes of ∼10 min and a super-period of ∼3 yr, as well as significantly refined estimates of the radii and mean orbital periods of all three planets. Dynamical modelling of the TTVs alone puts strong constraints on the mass ratio of planets c and d and on their eccentricities. When incorporating recently published constraints from radial velocity observations, we obtain masses of $M_{\mathrm{b}}=1.48\pm 0.18\, M_\oplus$, $M_{\mathrm{c}}=6.20\pm 0.31\, M_\oplus$, and $M_{\mathrm{d}}=4.20\pm 0.16\, M_\oplus$ for planets b, c, and d, respectively. We also detect small but significant eccentricities for all three planets : eb = 0.0167 ± 0.0084, ec = 0.0044 ± 0.0006, and ed = 0.0066 ± 0.0020. Our findings imply an Earth-like rocky composition for the inner planet, and Earth-like cores with an additional He/H2O atmosphere for the outer two. TOI-270 is now one of the best constrained systems of small transiting planets, and it remains an excellent target for atmospheric characterization.
Published: 2021

35. Characterizing Exoplanetary Atmospheres at High Resolution with SPIRou: Detection of Water on HD 189733 b

Author: Ray Jayawardhana, Pascal Fouqué, Romain Allart, Claire Moutou, Antoine Darveau-Bernier, Michael Radica, David Lafrenière, Baptiste Klein, J. H. C. Martins, Nuno C. Santos, Ryan Cloutier, João Gomes da Silva, Emily Deibert, Vincent Bourrier, Christophe Lovis, Étienne Artigau, Pedro Figueira, Jean-François Donati, Anne Boucher, Xavier Bonfils, Björn Benneke, Eder Martioli, René Doyon, Xavier Delfosse, Thierry Forveille, Jonathan Gagné, Stefan Pelletier, Guillaume Hébrard, Luc Arnold, Eric Gaidos, David Ehrenreich, Neil Cook, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), ANR-18-CE31-0019,SPlaSH,Recherche de planètes habitables avec SPIRou(2018), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)
Subjects: FOS: Physical sciences, Astrophysics, 01 natural sciences, law.invention, Atmosphere, Telescope, Planet, law, 0103 physical sciences, Hot Jupiter, Mixing ratio, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Exoplanet, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Bar (unit)
Abstract: We present the first exoplanet atmosphere detection made as part of the SPIRou Legacy Survey, a Large Observing Program of 300 nights exploiting the capabilities of SPIRou, the new near-infrared high-resolution (R ~ 70 000) spectro-polarimeter installed on the Canada-France-Hawaii Telescope (CFHT; 3.6-m). We observed two transits of HD 189733, an extensively studied hot Jupiter that is known to show prominent water vapor absorption in its transmission spectrum. When combining the two transits, we successfully detect the planet's water vapor absorption at 5.9 sigma using a cross-correlation t-test, or with a Delta BIC >10 using a log-likelihood calculation. Using a Bayesian retrieval framework assuming a parametrized T-P profile atmosphere models, we constrain the planet atmosphere parameters, in the region probed by our transmission spectrum, to the following values: VMR[H2O] = -4.4^{+0.4}_{-0.4}, and P_cloud >~ 0.2 bar (grey clouds), both of which are consistent with previous studies of this planet. Our retrieved water volume mixing ratio is slightly sub-solar although, combining it with the previously retrieved super-solar CO abundances from other studies would imply super-solar C/O ratio. We furthermore measure a net blue shift of the planet signal of -4.62^{+0.46}_{-0.44} km s-1, which is somewhat larger than many previous measurements and unlikely to result solely from winds in the planet's atmosphere, although it could possibly be explained by a transit signal dominated by the trailing limb of the planet. This large blue shift is observed in all the different detection/retrieval methods that were performed and in each of the two transits independently., 24 pages, 12 figures; accepted for publication in The Astronomical Journal
Published: 2021

36. TESS Hunt for Young and Maturing Exoplanets (THYME) IV: Three small planets orbiting a 120 Myr-old star in the Pisces--Eridanus stream

Author: Stephen R. Kane, Cesar Briceno, Keith Hawkins, Jessie L. Christiansen, Katharine Hesse, Jon M. Jenkins, Aaron C. Rizzuto, David R. Ciardi, Thiam-Guan Tan, Abderahmane Soubkiou, Logan A. Pearce, Jason L. Curtis, David W. Latham, Zouhair Benkhaldoun, John H. Livingston, Steven Villeneuva, Sara Seager, Nicholas M. Law, Elisabeth R. Newton, Natalia Guerrero, Diana Dragomir, Carl Ziegler, Roland Vanderspek, Joshua N. Winn, Alton Spencer, Ian J. M. Crossfield, Mackenna L. Wood, Coel Hellier, Guillermo Torres, Benjamin M. Tofflemire, Andrew W. Mann, Ryan Cloutier, Andrew Vanderburg, Björn Benneke, Chris Stockdale, George Zhou, Samuel N. Quinn, Dennis M. Conti, Alan M. Levine, Adam L. Kraus, Eric L. N. Jensen, Farisa Y. Morales, Pa Chia Thao, George R. Ricker, Varoujan Gorjian, Kevin I. Collins, Joseph D. Twicken, Jeffrey C. Smith, Michael W. Werner, Karen A. Collins, Laura Kreidberg, Elisa V. Quintana, and Bernie Shiao
Subjects: 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Q1, 01 natural sciences, Earth radius, Planet, 0103 physical sciences, Eridanus, 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Debris disk, Infrared excess, Astronomy, Astronomy and Astrophysics, Planetary system, Exoplanet, Photometry (astronomy), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, QB799, Astrophysics - Earth and Planetary Astrophysics
Abstract: Young exoplanets can offer insight into the evolution of planetary atmospheres, compositions, and architectures. We present the discovery of the young planetary system TOI 451 (TIC 257605131, Gaia DR2 4844691297067063424). TOI 451 is a member of the 120-Myr-old Pisces--Eridanus stream (Psc--Eri). We confirm membership in the stream with its kinematics, its lithium abundance, and the rotation and UV excesses of both TOI 451 and its wide binary companion, TOI 451 B (itself likely an M dwarf binary). We identified three candidate planets transiting in the TESS data and followed up the signals with photometry from Spitzer and ground-based telescopes. The system comprises three validated planets at periods of 1.9, 9.2 and 16 days, with radii of 1.9, 3.1, and 4.1 Earth radii, respectively. The host star is near-solar mass with V=11.0 and H=9.3 and displays an infrared excess indicative of a debris disk. The planets offer excellent prospects for transmission spectroscopy with HST and JWST, providing the opportunity to study planetary atmospheres that may still be in the process of evolving., 20 pages, appendix on UV excess
Published: 2021

37. Investigating the young AU Mic system with SPIRou: stellar magnetic field and close-in planet mass

Author: Baptiste Klein, Jean-François Donati, Claire Moutou, Xavier Delfosse, Xavier Bonfils, Eder Martioli, Pascal Fouqué, Ryan Cloutier, Etienne Artigau, René Doyon, Guillaume Hébrard, Julien Morin, Julien rameau, Peter Plavchan, and Eric Gaidos
Subjects: Young stars, 13. Climate action, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: Measuring the mean densities of close-in planets orbiting pre-main-sequence (PMS) stars is crucially needed by planet formation and evolution models. However, PMS stars exhibit intense magnetic activity inducing fluctuations in both photometric and RV curves that overshadow planet signatures. As a result, no close-in planet younger than 25 Myr has a well-constrained bulk density. In this study, we present a spectropolarimetric and velocimetric analysis of 27 near-infrared observations of the nearby active 22 Myr-old red dwarf AU Microscopii collected with SPIRou at the end of the year 2019. We jointly model the planet and stellar activity RV components, resulting in a 3.9σσ-detection of the recently-discovered close-in Neptune-sized planet AU Mic b, with an estimated mass of 17.1+4.7−4.5−4.5+4.7M⊕⊕, implying a Neptune-like density for the planet. A consistent detection of the planet is independently obtained by simultaneously reconstructing the surface distribution of bright and dark inhomogeneities and estimating the planet parameters using Doppler imaging (DI). Using Zeeman-Doppler Imaging, we invert our time-series of intensity and circularly-polarized line profiles into distributions of brightness and large-scale magnetic field at the surface of the star and explore how these distributions are sheared by latitudinal differential rotation. Finally, we investigate the magnetic activity of AU Mic by computing various indicators and found that the disk-integrated magnetic flux density correlates best with the stellar activity RV signal, in line with recent solar observations.
Published: 2021
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38. Three years of HARPS-N high-resolution spectroscopy and precise radial velocity data for the Sun

Author: Alessandro Sozzetti, Luca Malavolta, M. Cecconi, Raphaëlle D. Haywood, Ennio Poretti, Damien Ségransan, Ken Rice, Lars A. Buchhave, L. Riverol, David F. Phillips, C. Riverol, Danuta Sosnowska, Stéphane Udry, Annelies Mortier, Heather M. Cegla, A. Collier Cameron, M. Gonzalez, Mercedes López-Morales, Emilio Molinari, F. Alesina, Francesco Pepe, David W. Latham, Samantha Thompson, Xavier Dumusque, Giuseppina Micela, N. Buchschacher, Adriano Ghedina, J. Burnier, T. G. Wilson, Rosario Cosentino, Matteo Pinamonti, Marcello Lodi, C. Lovis, M. Cretignier, Jesus Maldonado, J. San Juan, Ryan Cloutier, H. Perez Ventura, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Mortier, Annelies [0000-0001-7254-4363], and Apollo - University of Cambridge Repository
Subjects: planets and satellites: detection, astro-ph.SR, T-NDAS, FOS: Physical sciences, Context (language use), Astrophysics, astronomical databases: miscellaneous, 01 natural sciences, Software, Sun: activity, 0103 physical sciences, techniques: radial velocities, Astronomical databases: miscellaneous, Instrumentation: spectrographs, Methods: data analysis, Planets and satellites: detection, Techniques: radial velocities, QB Astronomy, activity [Sun], spectrographs [Instrumentation], data analysis [Methods], Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Spectrograph, Solar and Stellar Astrophysics (astro-ph.SR), QC, instrumentation: spectrographs, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, radial velocities [Techniques], 010308 nuclear & particles physics, business.industry, Astronomy and Astrophysics, methods: data analysis, Solar telescope, Radial velocity, Data set, Stars, detection [Planets and satellites], QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, astro-ph.EP, miscellaneous [Astronomical databases], Astrophysics - Instrumentation and Methods for Astrophysics, business, astro-ph.IM, Astrophysics - Earth and Planetary Astrophysics, Data reduction
Abstract: The solar telescope connected to HARPS-N has been observing the Sun since the summer of 2015. Such high-cadence, long-baseline data set is crucial for understanding spurious radial-velocity signals induced by our Sun and by the instrument. On the instrumental side, this data set allowed us to detect sub-\ms\,systematics that needed to be corrected for. The goal of this manuscript is to i) present a new data reduction software for HARPS-N, ii) demonstrate the improvement brought by this new software on the first three years of the HARPS-N solar data set, and iii) release all the obtained solar products, from extracted spectra to precise radial velocities. To correct for the instrumental systematics observed in the data reduced with the current version of the HARPS-N data reduction software (DRS version 3.7), we adapted the newly available ESPRESSO DRS (version 2.2.3) to HARPS-N and developed new optimized recipes for the spectrograph. We then compared the first three years of HARPS-N solar data reduced with the current and new DRS. The most significant improvement brought by the new DRS is a strong decrease in the day-to-day radial-velocity scatter, from 1.27 to 1.07\ms; this is thanks to a more robust method to derive wavelength solutions, but also to the use of calibrations closer in time. The newly derived solar radial-velocities are also better correlated with the chromospheric activity level of the Sun on the long-term, with a Pearson correlation coefficient of 0.93 compared to 0.77 before, which is expected from our understanding of stellar signals. Finally, we also discuss how HARPS-N spectral ghosts contaminate the measurement of the calcium activity index, and present an efficient technique to derive an index free of instrumental systematics. This paper presents a new data reduction software for HARPS-N, and demonstrates its improvements [...], Comment: 20 pages, 15 figures, 2 tables, version accepted for publication in Astronomy and Astrophysics
Published: 2021

39. TOI-954 b and K2-329 b: Short-period saturn-mass planets that test whether irradiation leads to inflation

Author: David W. Latham, Rhodes Hart, Richard P. Schwarz, Matías R. Díaz, Ryan Cloutier, George Zhou, Matthew W. Mengel, Felipe Rojas, George R. Ricker, Jeffrey D. Crane, Andrés Jordán, Joshua N. Winn, Jennifer Burt, Thomas Henning, Lizhou Sha, Brett C. Addison, Erin Snoddy, Jonathan Horner, Eric L. N. Jensen, Jack Okumura, Rafael Brahm, Christopher E. Henze, Holger Drass, Norio Narita, Ian J. M. Crossfield, Benjamin T. Montet, Peter Plavchan, Michael Vezie, John H. Livingston, Hui Zhang, Roland Vanderspek, Keivan G. Stassun, Carl Ziegler, Allyson Bieryla, Karen A. Collins, David Nespral, Thiam-Guan Tan, Stephen R. Kane, Kaloyan Penev, Louise D. Nielsen, Steven Villanueva, Akshata Krishnamurthy, Luigi Mancini, Robert A. Wittenmyer, Joel D. Hartman, Eric B. Ting, Andrew Vanderburg, G. Ottoni, Johanna Teske, John F. Kielkopf, Sara Seager, Knicole D. Colón, Janis Hagelberg, Mauro Barbieri, A. Zapata, Duncan J. Wright, Chelsea X. Huang, François Bouchy, Stéphane Udry, Elisabeth Matthews, Andrew W. Mann, Paula Sarkis, Sharon X. Wang, Jon M. Jenkins, Diana Dragomir, Motohide Tamura, Pascal Torres, Gáspár Á. Bakos, Joseph E. Rodriguez, Daniel Bayliss, Avi Shporer, Néstor Espinoza, and Adina D. Feinstein
Subjects: 010504 meteorology & atmospheric sciences, Hot Jupiters, RV, FOS: Physical sciences, Astrophysics, 01 natural sciences, Photometry, Planet, High resolution spectroscopy, 0103 physical sciences, Hot Jupiter, Spectroscopy, Exoplanet systems, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Settore FIS/05, Subgiant, Astronomy and Astrophysics, Radius, Transit photometry, Radial velocity, Orbit, Photometry (astronomy), 13. Climate action, Space and Planetary Science, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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
Published: 2021
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40. A planetary system with two transiting mini-Neptunes near the radius valley transition around the bright M dwarf TOI-776

Author: Enric Palle, Eric L. N. Jensen, David Charbonneau, Iskra Georgieva, Priyanka Chaturvedi, Juan Cabrera, E. Goffo, Christopher E. Henze, Ian J. M. Crossfield, Davide Gandolfi, Massimiliano Esposito, Carina M. Persson, Ana Glidden, Karen A. Collins, R. C. Kidwell, Florian Rodler, C. Ziegler, Jack J. Lissauer, Vincent Van Eylen, Grzegorz Nowak, E. W. Guenther, George R. Ricker, Oscar Barragán, Martin Paegert, Emil Knudstrup, Artie P. Hatzes, Thiam-Guan Tan, Malcolm Fridlund, M. C. Nixon, Hans J. Deeg, David W. Latham, Nikku Madhusudhan, S. Grziwa, Seth Redfield, John F. Kielkopf, Teruyuki Hirano, Luisa M. Serrano, Sz. Csizmadia, Sara Seager, John H. Livingston, Jon M. Jenkins, Judith Korth, Petr Kabath, Kevin I. Collins, Cesar Briceno, Eric B. Ting, Knicole D. Colón, K. W. F. Lam, Karan Molaverdikhani, Robert F. Goeke, Joshua E. Schlieder, Joshua N. Winn, Nicholas J. Scott, Jonathan Irwin, Elisabeth Matthews, S. Albrecht, J. Šubjak, Fei Dai, Steve B. Howell, Rafael Luque, Roland Vanderspek, Ismael Mireles, Ryan Cloutier, Norio Narita, William D. Cochran, Andrew W. Mann, Nikku, Madhusudhan [0000-0002-4869-000X], and Apollo - University of Cambridge Repository
Subjects: Extrasolare Planeten und Atmosphären, Rotation period, 010504 meteorology & atmospheric sciences, Stellar mass, FOS: Physical sciences, Individual, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Photometric, individual: LP 961-53 [Stars], 01 natural sciences, Spectral line, techniques: photometric, Planet, low-mass [Stars], stars: low-mass, 0103 physical sciences, techniques: radial velocities, Radial Velocities, Astrophysics::Solar and Stellar Astrophysics, Planetary Systems, Low-Mass, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), radial velocities [Techniques], photometric [Techniques], stars: individual: LP 961-53, Astronomy and Astrophysics, Radius, Planetary system, Stars, Exoplanet, Techniques, Planetary systems, 13. Climate action, Space and Planetary Science, LP 961-53, lanetary systems – techniques: photometric – techniques: radial velocities – stars: individual: LP 961-53 – stars: low-mass, Astrophysics::Earth and Planetary Astrophysics, Stars: individual: LP 961-53, Stars: low-mass, Techniques: photometric, Techniques: radial velocities, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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
Published: 2021
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41. Mass and density of the transiting hot and rocky super-Earth LHS 1478 b (TOI-1640 b)

Author: Stefan Dreizler, Cristina Rodríguez-López, Víctor J. S. Béjar, P. Schöfer, Néstor Espinoza, Karen A. Collins, Alexander Rudat, Ryan Cloutier, Richard P. Nelson, Trifon Trifonov, David W. Latham, J. Kemmer, Enric Palle, E. Girardin, Mayuko Mori, Masayuki Kuzuhara, D. Montes, Chris Stockdale, M. Kunimoto, Ignasi Ribas, Artie P. Hatzes, M. Soto, Roland Vanderspek, Norio Narita, Eric L. N. Jensen, Andreas Quirrenbach, Karan Molaverdikhani, J. A. Caballero, David Charbonneau, M. Cortés-Contreras, P. Bluhm, Ansgar Reiners, D. Watanabe, Jonathan Irwin, Guillem Anglada-Escudé, S. Pedraz, Jorge Lillo-Box, Hiroki Harakawa, Christopher J. Burke, Teruyuki Hirano, Masashi Omiya, Joshua E. Schlieder, Juan Carlos Morales, Takayuki Kotani, Tomoyuki Kudo, Benjamin V. Rackham, P. Guerra, D. A. Caldwell, Motohide Tamura, Jon M. Jenkins, V. M. Passegger, P. J. Amado, Kiyoe Kawauchi, Andreas Schweitzer, A. Selezneva, Ministerio de Economía y Competitividad (España), Max Planck Society, European Commission, Generalitat de Catalunya, Ministerio de Ciencia, Innovación y Universidades (España), Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFÍSICA DE CANARIAS (IAC), SEV-2015-0548, Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Soto, M. G. [0000-0001-9743-5649], Deutsche Forschungsgemeinschaft (DFG), Ministerio de Economía y Competitividad (MINECO), Junta de Andalucía, Science and Technology Facilities Council (STFC), National Aeronautics and Space Administration (NASA), Agencia Estatal de Investigación (AEI), and Japan Society for the Promotion of Science (JSPS)
Subjects: Astrofísica, 010504 meteorology & atmospheric sciences, Red dwarf, fundamental parameters [Planets and satellites], FOS: Physical sciences, Astrophysics, Type (model theory), 7. Clean energy, 01 natural sciences, Planet, 0103 physical sciences, 14. Life underwater, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Super-Earth, radial velocities [Techniques], photometric [Techniques], Astronomy and Astrophysics, Planets and satellites: detection, Effective temperature, Exoplanet, Planets and satellites: fundamental parameters, Astronomía, Stars, detection [Planets and satellites], 13. Climate action, Space and Planetary Science, Techniques: radial velocities, Terrestrial planet, Techniques: photometric, Astrophysics - Earth and Planetary Astrophysics
Abstract: 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.
Published: 2021
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42. Investigating the young AU Mic system with SPIRou: large-scale stellar magnetic field and close-in planet mass

Author: Claire Moutou, Peter Plavchan, Étienne Artigau, Xavier Bonfils, Jean-François Donati, Pascal Fouqué, Julien Rameau, Baptiste Klein, Ryan Cloutier, Eder Martioli, Guillaume Hébrard, Julien Morin, Xavier Delfosse, René Doyon, Eric Gaidos, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Radial velocity, Brightness, Debris disk, [SDU]Sciences of the Universe [physics], Planet, Stellar magnetic field, Differential rotation, Astrophysics, Surface brightness, Planetary mass
Abstract: Measuring the mean densities of close-in planets orbiting pre-main-sequence (PMS) stars is crucially needed by planet formation and evolution models. This requires to measure both planet radii, from the depth of their transit light curves, and masses, from the radial velocity (RV) wobbles induced by the planet on its host star. However, PMS stars exhibit intense magnetic activity responsible for fluctuations in both photometric and RV curves that are much stronger than planet signatures. As a result, no close-in planet younger than 25 Myr has a well-constrained bulk density.AU Microscopii (AU Mic) is a nearby active 22-Myr old M1 star around which a close-in transiting planet was recently detected from TESS and Spitzer light-curves (Plavchan et al., 2020). Despite velocimetric follow-ups in the optical domain, the authors reported no more than an upper limit for the planet mass due to the large dispersion induced by stellar activity in their RV time-series. The high stellar brightness, and the expected decrease in the amplitude of stellar activity RV signals from the optical to the near-infrared domains, makes the nIR (YJHK bands) spectropolarimeter SPIRou (Canada-France-Hawaii Telescope, atop Mauna Kea) the ideal instrument to measure the mass of AU Mic b. In this study, we present a spectropolarimetric and velocimetric analysis of 27 observations of AU Mic collected with SPIRou from September to November 2019. The dispersion of our RV time-series is about 45 m/s, ~2.5 times lower than that obtained in the optical domain. We jointly model the planet and stellar activity components of the RV data set, resulting in a 3.5σ detection a close-in transiting planet AU Mic b, with an estimated mass of 16.7 +/- 4.9 Earth mass, implying a Neptune-like bulk density of 1.3 +/- 0.4 g/cm³. A consistent detection of the planet is independently obtained by simultaneously reconstructing the surface brightness of the star and estimating the planet parameters using Zeeman-Doppler imaging (ZDI). Using ZDI, we invert our intensity and circularly-polarized spectra into surface brightness and large-scale magnetic field, resulting in a mainly poloidal and axisymmetric field of 475 G, dominated by a 450 G dipole tilted at 19° to the rotation axis towards phase 0.2. Moreover, we find that the large-scale magnetic field is sheared by solar-like differential rotation of 0.167 rad/d, twice as large as that shearing the spot/plage distribution. Finally, we compute various indicators of the stellar activity and study their rotational modulation and correlation with RVs. We find that the bisector inverse slope and small-scale magnetic field correlate best with the stellar activity RV signal. Surprisingly, chromospheric indices based on Helium I (HeI, 1083 nm) and Paschen Beta (PaB, 1282 nm) probe different regions of the stellar disc, HeI being mostly emitted around the magnetic equator while PaB emission is linked to the magnetic pole.AU Mic b already appears as a prime target for constraining planet formation and evolution models. Moreover, the interactions between the planet and the debris disk surrounding the system could give rise to promising synergies between photometric, spectroscopic and imaging techniques. Finally, AU Mic b is a primary candidate for an atmosphere characterization and, potentially, the detection of an extended H/He exosphere around AU Mic b with upcoming space- and ground-based missions.
Published: 2020

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

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

44. Spin-orbit alignment and magnetic activity in the young planetary system AU Mic

Author: Neil Cook, Andres Carmona, J. Berberian, Angelle Tanner, Eric Gaidos, Étienne Artigau, C. Moutou, Ryan Cloutier, Eder Martioli, A. Lecavelier des Etangs, Johanna Teske, T. Forveille, Julien Morin, Nadine Manset, Peter Plavchan, René Doyon, S. Dalal, B. Cale, Jean-François Donati, P. Fouqué, X. Delfosse, Songhu Wang, Guillaume Hébrard, B. Klein, Laboratório Nacional de Astrofísica, Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Inflammatory Bowel Disease Center,, Cedars-Sinai Medical Center, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Université du Québec à Rimouski (UQAR), Departement de physique and Observatoire du Mont Megantic, Université de Montréal (UdeM), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), Swiss Bee Research Centre, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, and ANR-18-CE31-0019,SPlaSH,Recherche de planètes habitables avec SPIRou(2018)
Subjects: FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Protoplanetary disk, 01 natural sciences, symbols.namesake, Planet, 0103 physical sciences, stars: activity, techniques: radial velocities, Astrophysics::Solar and Stellar Astrophysics, stars: individual: AU Mic, 010303 astronomy & astrophysics, planetary systems, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Debris disk, Zeeman effect, 010308 nuclear & particles physics, Stellar rotation, stars: magnetic field, Astronomy and Astrophysics, Planetary system, Radial velocity, Orbit, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, symbols, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We present high resolution near-infrared spectropolarimetric observations using the SPIRou instrument at CFHT during a transit of the recently detected young planet AU Mic b, with supporting spectroscopic data from iSHELL at IRTF. We detect Zeeman signatures in the Stokes V profiles, and measure a mean longitudinal magnetic field of $\overline{B}_\ell=46.3\pm0.7$~G. Rotationally modulated magnetic spots likely cause long-term variations of the field with a slope of $d{B_\ell}/dt=-108.7\pm7.7$~G/d. We apply the cross-correlation technique to measure line profiles and obtain radial velocities through CCF template matching. We find an empirical linear relationship between radial velocity and $B_\ell$, which allows us to estimate the radial velocity variations which stellar activity induces through rotational modulation of spots for the five hours of continuous monitoring of AU Mic with SPIRou. We model the corrected radial velocities for the classical Rossiter-McLaughlin effect, using MCMC to sample the posterior distribution of the model parameters. This analysis shows that the orbit of AU Mic b is prograde and aligned with the stellar rotation axis with a sky-projected spin-orbit obliquity of $\lambda=0^{+18}_{-15}$ degrees. The aligned orbit of AU Mic b indicates that it formed in the protoplanetary disk that evolved to the current debris disk around AU Mic., Comment: Manuscript accepted for publication on 07/08/2020 as a Letter in Astronomy and Astrophysics, section 1
Published: 2020

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

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

46. The TESS-Keck Survey. I. A Warm Sub-Saturn-mass Planet and a Caution about Stray Light in TESS Cameras

Author: M. F. Andersen, Jeffrey C. Smith, Lauren M. Weiss, Enric Palle, Andrew W. Mayo, Teo Mocnik, Robert F. Goeke, David W. Latham, Ashley Chontos, Aida Behmard, Sara Seager, Howard Isaacson, Courtney D. Dressing, Daryll LaCourse, Judah Van Zandt, Joshua E. Schlieder, Monika Lendl, Chelsea X. Huang, Steven Giacalone, Paul A. Dalba, Joshua N. Winn, Erik A. Petigura, Joseph E. Rodriguez, Douglas A. Caldwell, Corey Beard, Roland Vanderspek, Stephen R. Kane, Lea A. Hirsch, Steven Villanueva, Martti H. Kristiansen, Nicholas Scarsdale, Emil Knudstrup, William Fong, Lee J. Rosenthal, Andrew Vanderburg, Paul Robertson, Ryan A. Rubenzahl, Samuel N. Quinn, Michelle L. Hill, George R. Ricker, Diana Dragomir, Molly R. Kosiarek, Arpita Roy, Tansu Daylan, Ian J. M. Crossfield, David R. Ciardi, Pamela Rowden, Natalie M. Batalha, Mark E. Rose, Allyson Bieryla, Gilbert A. Esquerdo, Keivan G. Stassun, Daniel J. Stevens, Jack Lubin, Joshua Pepper, Andrew W. Howard, Jon M. Jenkins, Benjamin J. Fulton, Arvind F. Gupta, H. P. Osborn, Tom Jacobs, Joseph M. Akana Murphy, Xinyu Yao, Daniel Huber, Frank Grundahl, and Ryan Cloutier
Subjects: Dwarf star, Radial velocity, 010504 meteorology & atmospheric sciences, Exoplanet astronomy, FOS: Physical sciences, 01 natural sciences, METHANE, Planet, 0103 physical sciences, Exoplanet detection methods, Direct imaging, Transit (astronomy), 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Spectroscopy, 0105 earth and related environmental sciences, Physics, JUPITER, Earth and Planetary Astrophysics (astro-ph.EP), ERROR-CORRECTION, Exoplanets, Astronomy, Astronomy and Astrophysics, Surface gravity, Light curve, Orbital period, Exoplanet, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, F dwarf stars, STATISTICAL PROPERTIES, Transit photometry, Astrophysics - Instrumentation and Methods for Astrophysics, STARS, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the detection of a Saturn-size exoplanet orbiting HD 332231 (TOI 1456) in light curves from the Transiting Exoplanet Survey Satellite (TESS). HD 332231, an F8 dwarf star with a V-band magnitude of 8.56, was observed by TESS in Sectors 14 and 15. We detect a single-transit event in the Sector 15 presearch data conditioning (PDC) light curve. We obtain spectroscopic follow-up observations of HD 332231 with the Automated Planet Finder, Keck I, and SONG telescopes. The orbital period we infer from the radial velocity (RV) observations leads to the discovery of another transit in Sector 14 that was masked by PDC due to scattered light contamination. A joint analysis of the transit and RV data confirms the planetary nature of HD 332231 b, a Saturn-size ($0.867^{+0.027}_{-0.025} \; R_{\rm J}$), sub-Saturn-mass ($0.244\pm0.021 \; M_{\rm J}$) exoplanet on a 18.71 day circular orbit. The low surface gravity of HD 332231 b and the relatively low stellar flux it receives make it a compelling target for transmission spectroscopy. Also, the stellar obliquity is likely measurable via the Rossiter-McLaughlin effect, an exciting prospect given the 0.14 au orbital separation of HD 332231 b. The spectroscopic observations do not provide substantial evidence for any additional planets in the HD 332231 system, but continued RV monitoring is needed to further characterize this system. We also predict that the frequency and duration of masked data in the PDC light curves for TESS Sectors 14-16 could hide transits of some exoplanets with orbital periods between 10.5 and 17.5 days., Comment: 17 pages, 9 figures, 4 tables. Published in the Astronomical Journal
Published: 2020

47. A hot terrestrial planet orbiting the bright M dwarf L 168-9 unveiled by TESS

Author: Sharon X. Wang, Diana Dragomir, Étienne Artigau, Pedro Figueira, Z. Essack, Andrés Jordán, David R. Anderson, Stéphane Udry, Nicholas M. Law, Thomas Henning, Roland Vanderspek, Rhodes Hart, Howard M. Relles, T. Forveille, C. Ziegler, C. Lovis, J. Villasenor, Pascal Torres, Jon M. Jenkins, Johanna Teske, Rodrigo F. Díaz, Joshua N. Winn, J. R. De Medeiros, David Charbonneau, Ryan Cloutier, Ian J. M. Crossfield, Jose-Manuel Almenara, Fabo Feng, Daniel A. Nusdeo, Keivan G. Stassun, S. Shectman, Nuno C. Santos, Dennis M. Conti, Damien Ségransan, Jennifer G. Winters, Ana Glidden, James S. Jenkins, N. Guerrero, François Bouchy, Misty Davies, Sara Seager, Andrew W. Mann, C. Melo, Avi Shporer, Tianjun Gan, Coel Hellier, Giovanni Isopi, Néstor Espinoza, René Doyon, Elliott P. Horch, Rafael Brahm, Jason D. Eastman, Xavier Bonfils, Jeffrey C. Smith, Francesco Pepe, David W. Latham, John F. Kielkopf, Karen A. Collins, Nicola Astudillo-Defru, R. P. Butler, Cesar Briceno, X. Delfosse, Felipe Murgas, Mark E. Rose, George Zhou, Ronald E. Mennickent, L. Mignon, George R. Ricker, F. Mallia, Jeffrey D. Crane, Departamento de Matemática y Fı́sica Aplicadas [Concepcion] (DMFA), Universidad Católica de la Santísima Concepción (UCSC), Université du Québec à Rimouski (UQAR), Center for Space Research [Cambridge] (CSR), Massachusetts Institute of Technology (MIT), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)
Subjects: 010504 meteorology & atmospheric sciences, Library science, FOS: Physical sciences, RADIAL VELOCITIES [TECHNIQUES], Astrophysics, Q1, LATE-TYPE [STARS], 01 natural sciences, purl.org/becyt/ford/1 [https], 0103 physical sciences, PLANETARY SYSTEMS, INDIVIDUAL: L 168-9 [STARS], 010303 astronomy & astrophysics, QB600, QC, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), European research, Astronomy and Astrophysics, purl.org/becyt/ford/1.3 [https], PHOTOMETRIC [TECHNIQUES], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Christian ministry, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics, QB799
Abstract: We report the detection of a transiting super-Earth-sized planet (R=1.39+-0.09 Rearth) in a 1.4-day orbit around L 168-9 (TOI-134),a bright M1V dwarf (V=11, K=7.1) located at 25.15+-0.02 pc. The host star was observed in the first sector of the Transiting Exoplanet Survey Satellite (TESS) mission and, for confirmation and planet mass measurement, was followed up with ground-based photometry, seeing-limited and high-resolution imaging, and precise radial velocity (PRV) observations using the HARPS and PFS spectrographs. Combining the TESS data and PRV observations, we find the mass of L168-9 b to be 4.60+-0.56 Mearth, and thus the bulk density to be 1.74+0.44-0.33 times larger than that of the Earth. The orbital eccentricity is smaller than 0.21 (95% confidence). This planet is a Level One Candidate for the TESS Mission's scientific objective - to measure the masses of 50 small planets - and is one of the most observationally accessible terrestrial planets for future atmospheric characterization., Comment: 14 pages, 8 figures, 3 tables. Accepted for publication in astronomy and Astrophysics
Published: 2020

48. The First Habitable Zone Earth-Sized Planet From TESS II: $Spitzer$ Confirms TOI-700 d

Author: J. Villasenor, Zachory K. Berta-Thompson, Eric D. Lopez, Jon M. Jenkins, Douglas A. Caldwell, Courtney D. Dressing, Patricia T. Boyd, Joseph D. Twicken, Emily A. Gilbert, Jason D. Eastman, David W. Latham, Sara Seager, Stephen R. Kane, Ryan Cloutier, Joshua E. Schlieder, Natalia Guerrero, Elisa V. Quintana, Joshua N. Winn, Eugene Chiang, Andrew W. Mann, Karen A. Collins, George R. Ricker, Maximilian N. Günther, Caroline V. Morley, Philip S. Muirhead, Thomas Barclay, John P. Doty, Gabrielle Suissa, Chelsea X. Huang, Alan M. Levine, Roland Vanderspek, Eve J. Lee, Andrew Vanderburg, David Charbonneau, Knicole D. Colón, Laura Kreidberg, David R. Ciardi, Elisabeth R. Newton, Alton Spencer, Mark E. Rose, Joseph E. Rodriguez, Tianjun Gan, Sebastian Zieba, Jessie L. Christiansen, Samuel N. Quinn, and Ravi Kumar Kopparapu
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Planetary habitability, FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, Light curve, 01 natural sciences, Exoplanet, Radial velocity, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Transit (astronomy), Astrophysics - Instrumentation and Methods for Astrophysics, 010303 astronomy & astrophysics, Circumstellar habitable zone, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present $Spitzer$ 4.5$��$m observations of the transit of TOI-700 d, a habitable zone Earth-sized planet in a multiplanet system transiting a nearby M-dwarf star (TIC 150428135, 2MASS J06282325-6534456). TOI-700 d has a radius of $1.144^{+0.062}_{-0.061}R_\oplus$ and orbits within its host star's conservative habitable zone with a period of 37.42 days ($T_\mathrm{eq} \sim 269$K). TOI-700 also hosts two small inner planets (R$_b$=$1.037^{+0.065}_{-0.064}R_\oplus$ & R$_c$=$2.65^{+0.16}_{-0.15}R_\oplus$) with periods of 9.98 and 16.05 days, respectively. Our $Spitzer$ observations confirm the TESS detection of TOI-700 d and remove any remaining doubt that it is a genuine planet. We analyze the $Spitzer$ light curve combined with the 11 sectors of TESS observations and a transit of TOI-700 c from the LCOGT network to determine the full system parameters. Although studying the atmosphere of TOI-700 d is not likely feasible with upcoming facilities, it may be possible to measure the mass of TOI-700 d using state-of-the-art radial velocity instruments (expected RV semi-amplitude of $\sim$70 cm/s)., 14 Pages, 5 Figures, 2 Tables, Accepted to AJ
Published: 2020
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49. Investigating the young AU~Mic system with SPIRou: large-scale stellar magnetic field and close-in planet mass

Author: Claire Moutou, Eder Martioli, Baptiste Klein, Jean-François Donati, Eric Gaidos, Xavier Delfosse, Julien Rameau, Étienne Artigau, René Doyon, Ryan Cloutier, Guillaume Hébrard, Pascal Fouqué, Xavier Bonfils, Julien Morin, Peter Plavchan, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and ANR-18-CE31-0019,SPlaSH,Recherche de planètes habitables avec SPIRou(2018)
Subjects: Brightness, polarimetric -techniques, imaging -stars, FOS: Physical sciences, Astrophysics, magnetic fields, 01 natural sciences, formation -stars, Planet, radial velocities -planets and satellites, 0103 physical sciences, Differential rotation, Astrophysics::Solar and Stellar Astrophysics, Surface brightness, individual, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), AU Microscopii -stars, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Debris disk, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Stellar magnetic field, Astronomy and Astrophysics, Radial velocity, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics, techniques, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present a velocimetric and spectropolarimetric analysis of 27 observations of the 22-Myr M1 star AU Microscopii (Au Mic) collected with the high-resolution $YJHK$ (0.98-2.35 $\mu$m) spectropolarimeter SPIRou from 2019 September 18 to November 14. Our radial velocity (RV) time-series exhibits activity-induced fluctuations of 45 m/s RMS, about three times smaller than those measured in the optical domain, that we filter using Gaussian Process Regression. We report a 3.9$\sigma$-detection of the recently-discovered 8.46-d transiting planet AU Mic b, with an estimated mass of $17.1^{+4.7}_{-4.5}$ M$_{\odot}$ and a bulk density of $1.3 \pm 0.4$ g/cm$^{-3}$, inducing a RV signature of semi-amplitude $K=8.5^{+2.3}_{-2.2}$ m/s in the spectrum of its host star. A consistent detection is independently obtained when we simultaneously image stellar surface inhomogeneities and estimate the planet parameters with Zeeman-Doppler Imaging (ZDI). Using ZDI, we invert the time series of unpolarized and circularly-polarized spectra into surface brightness and large-scale magnetic maps. We find a mainly poloidal and axisymmetric field of 475 G, featuring, in particular, a dipole of 450 G tilted at 19{\deg} to the rotation axis. Moreover, we detect a strong differential rotation of d$\Omega = 0.167 \pm 0.009$ rad/d shearing the large-scale field, about twice stronger than that shearing the brightness distribution, suggesting that both observables probe different layers of the convective zone. Even though we caution that more RV measurements are needed to accurately pin down the planet mass, AU Mic b already appears as a prime target for constraining planet formation models, studying the interactions with the surrounding debris disk, and characterizing its atmosphere with upcoming space- and ground-based missions., Comment: 19 pages, 20 figures, MNRAS, in press
Published: 2020
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50. Evolution of the radius valley around low mass stars from $Kepler$ and $K2$

Author: Ryan Cloutier and Kristen Menou
Subjects: 010504 meteorology & atmospheric sciences, Stellar mass, FOS: Physical sciences, Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Center (category theory), Astronomy and Astrophysics, Radius, Photoevaporation, Radial velocity, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Low Mass, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present calculations of the occurrence rate of small close-in planets around low mass dwarf stars using the known planet populations from the $Kepler$ and $K2$ missions. Applying completeness corrections clearly reveals the radius valley in the maximum a-posteriori occurrence rates as a function of orbital separation and planet radius. We measure the slope of the valley to be $r_{p,\text{valley}} \propto F^{-0.060\pm 0.025}$ which bears the opposite sign from that measured around Sun-like stars thus suggesting that thermally driven atmospheric mass loss may not dominate the evolution of planets in the low stellar mass regime or that we are witnessing the emergence of a separate channel of planet formation. The latter notion is supported by the relative occurrence of rocky to non-rocky planets increasing from $0.5\pm 0.1$ around mid-K dwarfs to $8.5\pm 4.6$ around mid-M dwarfs. Furthermore, the center of the radius valley at $1.54\pm 0.16$ R$_{\oplus}$ is shown to shift to smaller sizes with decreasing stellar mass in agreement with physical models of photoevaporation, core-powered mass loss, and gas-poor formation. Although current measurements are insufficient to robustly identify the dominant formation pathway of the radius valley, such inferences may be obtained by $TESS$ with $\mathcal{O}(85,000)$ mid-to-late M dwarfs observed with 2-minute cadence. The measurements presented herein also precisely designate the subset of planetary orbital periods and radii that should be targeted in radial velocity surveys to resolve the rocky to non-rocky transition around low mass stars., Comment: Submitted to AAS journals. 23 pages. Table data included as csv files in source. 15 figures including 6 interactive figures when viewed in Adobe Acrobat
Published: 2019
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