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172 results on '"Xavier Dumusque"'

1. 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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2. The K2 and TESS Synergy. III. Search and Rescue of the Lost Ephemeris for K2's First Planet

Author

Erica Thygesen, Joseph E. Rodriguez, Zoë L. de Beurs, Andrew Vanderburg, John H. Livingston, Jonathon Irwin, Alexander Venner, Michael Cretignier, Karen A. Collins, Allyson Bieryla, David Charbonneau, Ian J. M. Crossfield, Xavier Dumusque, John Kielkopf, David W. Latham, and Michael Werner

Subjects
Exoplanet astronomy, Exoplanet systems, Exoplanet catalogs, Exoplanets, Ephemerides, Transits, Astronomy, QB1-991
Abstract

K2-2 b/HIP 116454 b, the first exoplanet discovery by K2 during its Two-Wheeled Concept Engineering Test, is a sub-Neptune (2.5 ± 0.1 R _⊕ , 9.7 ± 1.2 M _⊕ ) orbiting a relatively bright ( K _S = 8.03) K-dwarf star on a 9.1 day period. Unfortunately, due to a spurious follow-up transit detection and ephemeris degradation, the transit ephemeris for this planet was lost. In this work, we recover and refine the transit ephemeris for K2-2 b, showing a ∼40 σ discrepancy from the discovery results. To accurately measure the transit ephemeris and update the parameters of the system, we jointly fit space-based photometric observations from NASA’s K2, Transiting Exoplanet Survey Satellite, and Spitzer missions with new photometric observations from the ground, as well as radial velocities from HARPS-N that are corrected for stellar activity using a new modeling technique. Ephemerides becoming lost or significantly degraded, as is the case for most transiting planets, highlights the importance of systematically updating transit ephemerides with upcoming large efforts expected to characterize hundreds of exoplanet atmospheres. K2-2 b sits at the high-mass peak of the known radius valley for sub-Neptunes, and is now well-suited for transmission spectroscopy with current and future facilities. Our updated transit ephemeris will ensure no more than a 13 minute uncertainty through 2030.

Published
2024
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3. Surviving in the Hot-Neptune Desert: The Discovery of the Ultrahot Neptune TOI-3261b

Author

Emma Nabbie, Chelsea X. Huang, Jennifer A. Burt, David J. Armstrong, Eric E. Mamajek, Vardan Adibekyan, Sérgio G. Sousa, Eric D. Lopez, Daniel Thorngren, Jorge Fernández Fernández, Gongjie Li, James S. Jenkins, Jose I. Vines, João Gomes da Silva, Robert A. Wittenmyer, Daniel Bayliss, César Briceño, Karen A. Collins, Xavier Dumusque, Keith Horne, Marcelo Aron F. Keniger, Nicholas Law, Jorge Lillo-Box, Shang-Fei Liu, Andrew W. Mann, Louise D. Nielsen, Ares Osborn, Howard M. Relles, José J. Rodrigues, Juan Serrano Bell, Gregor Srdoc, Chris Stockdale, Paul A. Strøm, Cristilyn N. Watkins, Peter J. Wheatley, Duncan J. Wright, George Zhou, Carl Ziegler, George Ricker, Sara Seager, Roland Vanderspek, Joshua N. Winn, Jon M. Jenkins, Michael Fausnaugh, Michelle Kunimoto, Hugh P. Osborn, Samuel N. Quinn, and Bill Wohler

Subjects
Exoplanets, Transits, Radial velocity, Astronomy, QB1-991
Abstract

The recent discoveries of Neptune-sized ultra-short-period planets (USPs) challenge existing planet formation theories. It is unclear whether these residents of the Hot Neptune Desert have similar origins to smaller, rocky USPs, or if this discrete population is evidence of a different formation pathway altogether. We report the discovery of TOI-3261b, an ultrahot Neptune with an orbital period P = 0.88 day. The host star is a V = 13.2 mag, slightly supersolar metallicity ([Fe/H] ≃0.15), inactive K1.5 main-sequence star at d = 300 pc. Using data from the Transiting Exoplanet Survey Satellite and the Las Cumbres Observatory Global Telescope, we find that TOI-3261b has a radius of ${3.82}_{-0.35}^{+0.42}$ R _⊕ . Moreover, radial velocities from ESPRESSO and HARPS reveal a mass of ${30.3}_{-2.4}^{+2.2}$ M _⊕ , more than twice the median mass of Neptune-sized planets on longer orbits. We investigate multiple mechanisms of mass loss that can reproduce the current-day properties of TOI-3261b, simulating the evolution of the planet via tidal stripping and photoevaporation. Thermal evolution models suggest that TOI-3261b should retain an envelope potentially enriched with volatiles constituting ∼5% of its total mass. This is the second highest envelope mass fraction among ultrahot Neptunes discovered to date, making TOI-3261b an ideal candidate for atmospheric follow-up observations.

Published
2024
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4. The Extreme Stellar-signals Project. III. Combining Solar Data from HARPS, HARPS-N, EXPRES, and NEID

Author

Lily L. Zhao, Xavier Dumusque, Eric B. Ford, Joe Llama, Annelies Mortier, Megan Bedell, Khaled Al Moulla, Chad F. Bender, Cullen H. Blake, John M. Brewer, Andrew Collier Cameron, Rosario Cosentino, Pedro Figueira, Debra A. Fischer, Adriano Ghedina, Manuel Gonzalez, Samuel Halverson, Shubham Kanodia, David W. Latham, Andrea S. J. Lin, Gaspare Lo Curto, Marcello Lodi, Sarah E. Logsdon, Christophe Lovis, Suvrath Mahadevan, Andrew Monson, Joe P. Ninan, Francesco Pepe, Rachael M. Roettenbacher, Arpita Roy, Nuno C. Santos, Christian Schwab, Guđmundur Stefánsson, Andrew E. Szymkowiak, Ryan C. Terrien, Stephane Udry, Sam A. Weiss, François Wildi, Thibault Wildi, and Jason T. Wright

Subjects
Stellar activity, Solar activity, Spectrometers, Astronomical instrumentation, Radial velocity, Exoplanet detection methods, Astronomy, QB1-991
Abstract

We present an analysis of Sun-as-a-star observations from four different high-resolution, stabilized spectrographs—HARPS, HARPS-N, EXPRES, and NEID. With simultaneous observations of the Sun from four different instruments, we are able to gain insight into the radial velocity precision and accuracy delivered by each of these instruments and isolate instrumental systematics that differ from true astrophysical signals. With solar observations, we can completely characterize the expected Doppler shift contributed by orbiting Solar System bodies and remove them. This results in a data set with measured velocity variations that purely trace flows on the solar surface. Direct comparisons of the radial velocities measured by each instrument show remarkable agreement with residual intraday scatter of only 15–30 cm s ^−1 . This shows that current ultra-stabilized instruments have broken through to a new level of measurement precision that reveals stellar variability with high fidelity and detail. We end by discussing how radial velocities from different instruments can be combined to provide powerful leverage for testing techniques to mitigate stellar signals.

Published
2023
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5. TOI-4010: A System of Three Large Short-period Planets with a Massive Long-period Companion

Author

Michelle Kunimoto, Andrew Vanderburg, Chelsea X. Huang, M. Ryleigh Davis, Laura Affer, Andrew Collier Cameron, David Charbonneau, Rosario Cosentino, Mario Damasso, Xavier Dumusque, A. F. Martnez Fiorenzano, Adriano Ghedina, R. D. Haywood, Florian Lienhard, Mercedes López-Morales, Michel Mayor, Francesco Pepe, Matteo Pinamonti, Ennio Poretti, Jesús Maldonado, Ken Rice, Alessandro Sozzetti, Thomas G. Wilson, Stéphane Udry, Jay Baptista, Khalid Barkaoui, Juliette Becker, Paul Benni, Allyson Bieryla, Pau Bosch-Cabot, David R. Ciardi, Karen A. Collins, Kevin I. Collins, Elise Evans, Trent J. Dupuy, Maria V. Goliguzova, Pere Guerra, Adam Kraus, Jack J. Lissauer, Daniel Huber, Felipe Murgas, Enric Palle, Samuel N. Quinn, Boris S. Safonov, Richard P. Schwarz, Avi Shporer, Keivan G. Stassun, Jon M. Jenkins, David W. Latham, George R. Ricker, Sara Seager, Roland Vanderspek, Joshua Winn, Zahra Essack, Hannah M. Lewis, and Mark E. Rose

Subjects
Exoplanets, Hot Neptunes, Exoplanet systems, Transit photometry, Exoplanet dynamics, Astronomy, QB1-991
Abstract

We report the confirmation of three exoplanets transiting TOI-4010 (TIC-352682207), a metal-rich K dwarf observed by the Transiting Exoplanet Survey Satellite in Sectors 24, 25, 52, and 58. We confirm these planets with the High Accuracy Radial velocity Planet Searcher for the Northern Hemisphere radial velocity observations and measure their masses with 8−12% precision. TOI-4010 b is a sub-Neptune ( P = 1.3 days, ${R}_{p}={3.02}_{-0.08}^{+0.08}\,{R}_{\oplus }$ , ${M}_{p}={11.00}_{-1.27}^{+1.29}\,{M}_{\oplus }$ ) in the hot-Neptune desert, and is one of the few such planets with known companions. Meanwhile, TOI-4010 c ( P = 5.4 days, ${R}_{p}={5.93}_{-0.12}^{+0.11}\,{R}_{\oplus }$ , ${M}_{p}={20.31}_{-2.11}^{+2.13}\,{M}_{\oplus }$ ) and TOI-4010 d ( P = 14.7 days, ${R}_{p}={6.18}_{-0.14}^{+0.15}\,{R}_{\oplus }$ , ${M}_{p}={38.15}_{-3.22}^{+3.27}\,{M}_{\oplus }$ ) are similarly sized sub-Saturns on short-period orbits. Radial velocity observations also reveal a super-Jupiter-mass companion called TOI-4010 e in a long-period, eccentric orbit ( P ∼ 762 days and e ∼ 0.26 based on available observations). TOI-4010 is one of the few systems with multiple short-period sub-Saturns to be discovered so far.

Published
2023
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6. Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass

Author

Andrew W. Mayo, Courtney D. Dressing, Andrew Vanderburg, Charles D. Fortenbach, Florian Lienhard, Luca Malavolta, Annelies Mortier, Alejandro Núñez, Tyler Richey-Yowell, Emma V. Turtelboom, Aldo S. Bonomo, David W. Latham, Mercedes López-Morales, Evgenya Shkolnik, Alessandro Sozzetti, Marcel A. Agüeros, Luca Borsato, David Charbonneau, Rosario Cosentino, Stephanie T. Douglas, Xavier Dumusque, Adriano Ghedina, Rose Gibson, Valentina Granata, Avet Harutyunyan, R. D. Haywood, Gaia Lacedelli, Vania Lorenzi, Antonio Magazzù, A. F. Martinez Fiorenzano, Giuseppina Micela, Emilio Molinari, Marco Montalto, Domenico Nardiello, Valerio Nascimbeni, Isabella Pagano, Giampaolo Piotto, Lorenzo Pino, Ennio Poretti, Gaetano Scandariato, Stephane Udry, and Lars A. Buchhave

Subjects
Exoplanets, Exoplanet systems, Exoplanet atmospheres, Exoplanet detection methods, Radial velocity, Transits, Astronomy, QB1-991
Abstract

K2-136 is a late-K dwarf (0.742 ± 0.039 M _⊙ ) in the Hyades open cluster with three known, transiting planets and an age of 650 ± 70 Myr. Analyzing K2 photometry, we found that planets K2-136b, c, and d have periods of 8.0, 17.3, and 25.6 days and radii of 1.014 ± 0.050 R _⊕ , 3.00 ± 0.13 R _⊕ , and 1.565 ± 0.077 R _⊕ , respectively. We collected 93 radial velocity (RV) measurements with the High-Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph (Telescopio Nazionale Galileo) and 22 RVs with the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) spectrograph (Very Large Telescope). Analyzing HARPS-N and ESPRESSO data jointly, we found that K2-136c induced a semi-amplitude of 5.49 ± 0.53 m s ^−1 , corresponding to a mass of 18.1 ± 1.9 M _⊕ . We also placed 95% upper mass limits on K2-136b and d of 4.3 and 3.0 M _⊕ , respectively. Further, we analyzed Hubble Space Telescope and XMM-Newton observations to establish the planetary high-energy environment and investigate possible atmospheric loss. K2-136c is now the smallest planet to have a measured mass in an open cluster and one of the youngest planets ever with a mass measurement. K2-136c has ∼75% the radius of Neptune but is similar in mass, yielding a density of ${3.69}_{-0.56}^{+0.67}$ g cm ^−3 (∼2–3 times denser than Neptune). Mass estimates for K2-136b (and possibly d) may be feasible with more RV observations, and insights into all three planets’ atmospheres through transmission spectroscopy would be challenging but potentially fruitful. This research and future mass measurements of young planets are critical for investigating the compositions and characteristics of small exoplanets at very early stages of their lives and providing insights into how exoplanets evolve with time.

Published
2023
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7. 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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8. Kepler-102: Masses and Compositions for a Super-Earth and Sub-Neptune Orbiting an Active Star

Author

Casey L. Brinkman, James Cadman, Lauren Weiss, Eric Gaidos, Ken Rice, Daniel Huber, Zachary R. Claytor, Aldo S. Bonomo, Lars A. Buchhave, Andrew Collier Cameron, Rosario Cosentino, Xavier Dumusque, Aldo F. Martinez Fiorenzano, Adriano Ghedina, Avet Harutyunyan, Andrew Howard, Howard Isaacson, David W. Latham, Mercedes López-Morales, Luca Malavolta, Giuseppina Micela, Emilio Molinari, Francesco Pepe, David F. Philips, Ennio Poretti, Alessandro Sozzetti, and Stéphane Udry

Subjects
Exoplanets, Super Earths, Mini Neptunes, Extrasolar rocky planets, Gaussian Processes regression, Radial velocity, Astronomy, QB1-991
Abstract

Radial velocity (RV) measurements of transiting multiplanet systems allow us to understand the densities and compositions of planets unlike those in the solar system. Kepler-102, which consists of five tightly packed transiting planets, is a particularly interesting system since it includes a super-Earth (Kepler-102d) and a sub-Neptune-sized planet (Kepler-102e) for which masses can be measured using RVs. Previous work found a high density for Kepler-102d, suggesting a composition similar to that of Mercury, while Kepler-102e was found to have a density typical of sub-Neptune size planets; however, Kepler-102 is an active star, which can interfere with RV mass measurements. To better measure the mass of these two planets, we obtained 111 new RVs using Keck/HIRES and Telescopio Nazionale Galileo/HARPS-N and modeled Kepler-102's activity using quasiperiodic Gaussian process regression. For Kepler-102d, we report a mass upper limit M _d < 5.3 M _⊕ (95% confidence), a best-fit mass M _d = 2.5 ± 1.4 M _⊕ , and a density ρ _d = 5.6 ± 3.2 g cm ^−3 , which is consistent with a rocky composition similar in density to the Earth. For Kepler-102e we report a mass M _e = 4.7 ± 1.7 M _⊕ and a density ρ _e = 1.8 ± 0.7 g cm ^−3 . These measurements suggest that Kepler-102e has a rocky core with a thick gaseous envelope comprising 2%–4% of the planet mass and 16%–50% of its radius. Our study is yet another demonstration that accounting for stellar activity in stars with clear rotation signals can yield more accurate planet masses, enabling a more realistic interpretation of planet interiors.

Published
2023
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9. 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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11. TOI-2498 b: a hot bloated super-Neptune within the Neptune desert

Author

Ginger Frame, David J Armstrong, Heather M Cegla, Jorge Fernández Fernández, Ares Osborn, Vardan Adibekyan, Karen A Collins, Elisa Delgado Mena, Steven Giacalone, John F Kielkopf, Nuno C Santos, Sérgio G Sousa, Keivan G Stassun, Carl Ziegler, David R Anderson, Susana C C Barros, Daniel Bayliss, César Briceño, Dennis M Conti, Courtney D Dressing, Xavier Dumusque, Pedro Figueira, William Fong, Samuel Gill, Faith Hawthorn, Jon M Jenkins, Eric L N Jensen, Marcelo Aron F Keniger, David W Latham, Nicholas Law, Jack J Lissauer, Andrew W Mann, Louise D Nielsen, Hugh Osborn, Martin Paegert, Sara Seager, Richard P Schwarz, Avi Shporer, Gregor Srdoc, Paul A Strøm, Joshua N Winn, and Peter J Wheatley

Published
2023
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12. 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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14. HD 213885b: a transiting 1-d-period super-Earth with an Earth-like composition around a bright (V = 7.9) star unveiled by TESS

Author

Néstor Espinoza, Rafael Brahm, Thomas Henning, Andrés Jordán, Caroline Dorn, Felipe Rojas, Paula Sarkis, Diana Kossakowski, Martin Schlecker, Matías R Díaz, James S Jenkins, Claudia Aguilera-Gomez, Jon M Jenkins, Joseph D Twicken, Karen A Collins, Jack Lissauer, David J Armstrong, Vardan Adibekyan, David Barrado, Susana C C Barros, Matthew Battley, Daniel Bayliss, François Bouchy, Edward M Bryant, Benjamin F Cooke, Olivier D S Demangeon, Xavier Dumusque, Pedro Figueira, Helen Giles, Jorge Lillo-Box, Christophe Lovis, Louise D Nielsen, Francesco Pepe, Don Pollacco, Nuno C Santos, Sergio G Sousa, Stéphane Udry, Peter J Wheatley, Oliver Turner, Maxime Marmier, Damien Ségransan, George Ricker, David Latham, Sara Seager, Joshua N Winn, John F Kielkopf, Rhodes Hart, Geof Wingham, Eric L N Jensen, Krzysztof G Hełminiak, A Tokovinin, C Briceño, Carl Ziegler, Nicholas M Law, Andrew W Mann, Tansu Daylan, John P Doty, Natalia Guerrero, Patricia Boyd, Ian Crossfield, Robert L Morris, Christopher E Henze, and Aaron Dean Chacon

Published
2019
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15. Identifying Exoplanets with Deep Learning. IV. Removing Stellar Activity Signals from Radial Velocity Measurements Using Neural Networks.

Author

Zoe L. de Beurs, Andrew Vanderburg, Christopher J. Shallue, Xavier Dumusque, Andrew Collier Cameron, Lars A. Buchhave, Rosario Cosentino, Adriano Ghedina, Raphaëlle D. Haywood, Nicholas Langellier, David W. Latham, Mercedes López-Morales, Michel Mayor, Giusi Micela, Timothy W. Milbourne, Annelies Mortier, Emilio Molinari, Francesco Pepe, David F. Phillips, Matteo Pinamonti, Giampaolo Piotto, Ken Rice, Dimitar Sasselov, Alessandro Sozzetti, Stéphane Udry, and Christopher A. Watson

Published
2020

17. The EXPRES Stellar Signals Project II. State of the Field in Disentangling Photospheric Velocities

Author

Lily L. Zhao, Debra A. Fischer, Eric B. Ford, Alex Wise, Michaël Cretignier, Suzanne Aigrain, Oscar Barragan, Megan Bedell, Lars A. Buchhave, João D. Camacho, Heather M. Cegla, Jessi Cisewski-Kehe, Andrew Collier Cameron, Zoe L. de Beurs, Sally Dodson-Robinson, Xavier Dumusque, João P. Faria, Christian Gilbertson, Charlotte Haley, Justin Harrell, David W. Hogg, Parker Holzer, Ancy Anna John, Baptiste Klein, Marina Lafarga, Florian Lienhard, Vinesh Maguire-Rajpaul, Annelies Mortier, Belinda Nicholson, Michael L. Palumbo, Victor Ramirez Delgado, Christopher J. Shallue, Andrew Vanderburg, Pedro T. P. Viana, Jinglin Zhao, Norbert Zicher, Samuel H. C. Cabot, Gregory W. Henry, Rachael M. Roettenbacher, John M. Brewer, Joe Llama, Ryan R. Petersburg, and Andrew E. Szymkowiak

Published
2022
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18. TOI-824 b: A New Planet on the Lower Edge of the Hot Neptune Desert

Author

Jennifer A. Burt, Louise D. Nielsen, Samuel N. Quinn, Eric E. Mamajek, Elisabeth C. Matthews, George Zhou, Julia V. Seidel, Chelsea X. Huang, Eric Lopez, Maritza Soto, Jon Otegi, Keivan G. Stassun, Laura Kreidberg, Karen A. Collins, Jason D. Eastman, Joseph E. Rodriguez, Andrew Vanderburg, Samuel P. Halverson, Johanna K. Teske, Sharon X. Wang, R. Paul Butler, François Bouchy, Xavier Dumusque, Damien Segransen, Stephen A. Shectman, Jeffrey D. Crane, Fabo Feng, Benjamin T. Montet, Adina D. Feinstein, Yuri Beletski, Erin Flowers, Maximilian N. Günther, Tansu Daylan, Kevin I. Collins, Dennis M. Conti, Tianjun Gan, Eric L. N. Jensen, John F. Kielkopf, Thiam-Guan Tan, Ravit Helled, Caroline Dorn, Jonas Haldemann, Jack J. Lissauer, George R. Ricker, Roland Vanderspek, David W. Latham, S. Seager, Joshua N. Winn, Jon M. Jenkins, Joseph D. Twicken, Jeffrey C. Smith, Peter Tenenbaum, Scott Cartwright, Thomas Barclay, Joshua Pepper, Gilbert Esquerdo, and William Fong

Subjects
Astronomy, Astrophysics
Abstract

We report the detection of a transiting hot Neptune exoplanet orbiting TOI-824 (SCR J1448-5735), a nearby (d = 64 pc) K4V star, using data from the Transiting Exoplanet Survey Satellite. The newly discovered planet has a radius Rp = 2.93 ± 0.20 Rꚛ and an orbital period of 1.393 days. Radial velocity measurements using the Planet Finder Spectrograph and the High Accuracy Radial velocity Planet Searcher spectrograph confirm the existence of the planet, and we estimate its mass to be 18.47 ± 1.84 Mꚛ. The planet's mean density is ρ(p)= 4.03 (+0.98,-0.78)g/cu. cm, making it more than twice as dense as Neptune. TOI-824 b's high equilibrium temperature makes the planet likely to have a cloud-free atmosphere, and thus it is an excellent candidate for follow-up atmospheric studies. The detectability of TOI-824 b's atmosphere from both ground and space is promising and could lead to the detailed characterization of the most irradiated small planet at the edge of the hot Neptune desert that has retained its atmosphere to date.

Published
2020
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19. A remnant planetary core in the hot-Neptune desert

Author

David J. Armstrong, Théo A. Lopez, Vardan Adibekyan, Richard A. Booth, Edward M. Bryant, Karen A. Collins, Magali Deleuil, Alexandre Emsenhuber, Chelsea X. Huang, George W. King, Jorge Lillo-Box, Jack J. Lissauer, Elisabeth Matthews, Olivier Mousis, Louise D. Nielsen, Hugh Osborn, Jon Otegi, Nuno C. Santos, Sérgio G. Sousa, Keivan G. Stassun, Dimitri Veras, Carl Ziegler, Jack S. Acton, Jose M. Almenara, David R. Anderson, David Barrado, Susana C. C. Barros, Daniel Bayliss, Claudia Belardi, Francois Bouchy, César Briceño, Matteo Brogi, David J. A. Brown, Matthew R. Burleigh, Sarah L. Casewell, Alexander Chaushev, Kevin I. Collins, Knicole D. Colón, Benjamin F. Cooke, Ian J. M. Crossfield, Rodrigo F. Díaz, Elisa Delgado Mena, Olivier D. S. Demangeon, Caroline Dorn, Xavier Dumusque, Philipp Eigmüller, Michael Fausnaugh, Pedro Figueira, Tianjun Gan, Siddharth Gandhi, Samuel Gill, Erica J. Gonzales, Michael R. Goad, Ravit Helled, Saeed Hojjatpanah, Steve B. Howell, James Jackman, James S. Jenkins, Jon M. Jenkins, Eric L. N. Jensen, Grant M. Kennedy, David W. Latham, Nicholas Law, Monika Lendl, Michael Lozovsky, Andrew W. Mann, Maximiliano Moyano, James McCormac, Farzana Meru, Christoph Mordasini, Ares Osborn, Don Pollacco, Didier Queloz, Liam Raynard, George R. Ricker, Pamela Rowden, Alexandre Santerne, Joshua E. Schlieder, Sara Seager, Lizhou Sha, Thiam-Guan Tan, Rosanna H. Tilbrook, Eric Ting, Stéphane Udry, Roland Vanderspek, Christopher A. Watson, Richard G. West, Paul A. Wilson, Joshua N. Winn, Peter Wheatley, Jesus Noel Villasenor, Jose I. Vines, and Zhuchang Zhan

Subjects
Exobiology, Lunar And Planetary Science And Exploration
Abstract

The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune ‘desert’ (a region in mass–radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b, which is thought to have an unusually massive core, and recent discoveries such as LTT9779b and NGTS-4b, on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune’s but an anomalously large mass of 39.1(+2.7−2.6) Earth masses and a density of 5.2(+0.7−0.8) grams per cubic centimetre, similar to Earth’s. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than 3.9(+0.8−0.9) per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation. Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.

Published
2020
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20. 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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21. The SCORE project: finding Earth 2.0 Does life exist elsewhere in the Universe?

Author

Xavier Dumusque

Abstract

The SCORE project: finding Earth 2.0 Does life exist elsewhere in the Universe? The goal of the SCORE project is to enable the detection of other Earths orbiting bright, close-by Sun-like stars for which future ground and space-based missions will be able to characterise their atmosphere in the search for signatures of life elsewhere in the Universe.

Published
2022

22. 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

24. K2-111: an old system with two planets in near-resonance†

Author

Lars A. Buchhave, Valentina D'Odorico, Laura Affer, Dimitar Sasselov, Annelies Mortier, C. Allende Prieto, Christopher A. Watson, Aldo F. M. Fiorenzano, Paolo Molaro, A. Collier Cameron, Nuno C. Santos, Marco Riva, C. Lovis, Nelson J. Nunes, David Charbonneau, Jesus Maldonado, S. G. Sousa, Enric Palle, Giampaolo Piotto, Aldo S. Bonomo, Adriano Ghedina, Cristina Martins, Richard G. West, Andrew Vanderburg, David W. Latham, Giuseppina Micela, Vardan Adibekyan, Francesco Pepe, G. Lo Curto, Ken Rice, Mahmoudreza Oshagh, Avet Harutyunyan, Alexandre Cabral, Andrea Mehner, P. Di Marcantonio, Antonio Manescau, Rafael Rebolo, Matteo Pinamonti, M. R. Zapatero Osorio, François Bouchy, Baptiste Lavie, Denis Mégevand, Luca Malavolta, Stéphane Udry, David F. Phillips, David Ehrenreich, Jorge Lillo-Box, A. Suárez Mascareño, T. G. Wilson, S. C. C. Barros, Rosario Cosentino, Olivier Demangeon, M. Mayor, Xavier Dumusque, Mercedes López-Morales, Walter Boschin, E. Delgado Mena, Emilio Molinari, Serena Benatti, Alessandro Sozzetti, P. Figueira, Raphaëlle D. Haywood, Ennio Poretti, Stefano Cristiani, J. Haldemann, Yann Alibert, J. I. González Hernández, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Science and Technology Facilities Council (STFC), Istituto Nazionale di Astrofisica (INAF), Swiss National Science Foundation (SNSF), Fundação para a Ciência e a Tecnologia (FCT), National Aeronautics and Space Administration (NASA), European Research Council (ERC), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Cabral, A. [0000-0002-9433-871X], Suárez Mascareño, A. [0000-0002-3814-5323], Molaro, P. [0000-0002-0571-4163], Mena, E. D. [0000-0003-4434-2195], Buchhave, L. A. [0000-0003-1605-5666], Vanderburg, A. [0000-0001-7246-5438], Barros, S. [0000-0003-2434-3625], Haldemann, J. [0000-0003-1231-2389], Cosentino, R. [0000-0003-1784-1431], Sozzetti, A. [0000-0002-7504-365X], Adibekyan, V. [0000-0002-0601-6199], Wilson, T. G. [0000-0001-8749-1962], Cameron, A. [0000-0002-8863-7828], Santos, N. [0000-0003-4422-2919], Ministerio de Ciencia e Innovación (MICINN), Science and Technology Facilities Council (STFC), ST/R000824/1 ST/P000312/1 PTDC/FIS-AST/32113/2017, Istituto Nazionale Astrofisica (INAF) Agenzia Spaziale Italiana (ASI), 2018-16-HH.0, Swiss National Science Foundation (SNSF), 140649 152721 166227 184618, Fundação para a Ciência e a Tecnologia (FCT) through Investigador FCT, IF/00650/2015/CP1273/CT0001 IF/00849/2015/CP1273/CT0003 IF/00028/2014/CP1215/CT0002 IF/01312/2014/CP1215/CT0004 DL 57/2016/CP1364/CT0004, FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao, National Aeronautics and Space Administration (NASA), NNX17AB59G NAS5-26555 NNX13AC07G, Research Projects of National Relevance (PRIN), 201278X4FL, MCTES, PTDC/FIS-AST/32113/2017, European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (project FOUR ACES), ITA, USA, GBR, DEU, ESP, CHL, DNK, PRT, CHE, Mortier, Annelies [0000-0001-7254-4363], and Apollo - University of Cambridge Repository

Subjects
planets and satellites: detection, 010504 meteorology & atmospheric sciences, 530 Physics, stars: individual (K2-111), FOS: Physical sciences, Astrophysics, Spectroscopic, 01 natural sciences, spectroscopic [Techniques], techniques: photometric, Planet, individual [Stars], techniques: radial velocities, 0103 physical sciences, QB Astronomy, 010303 astronomy & astrophysics, QC, QB, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, radial velocities [Techniques], 520 Astronomy, individual (K2-111) [Stars], photometric [Techniques], Astronomy and Astrophysics, 3rd-DAS, Radius, 500 Science, Planetary system, 620 Engineering, Orbital period, Radial velocity, detection [Planets and satellites], Photometry (astronomy), QC Physics, 13. Climate action, Space and Planetary Science, astro-ph.EP, Terrestrial planet, techniques: spectroscopic, K2-111, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract

This paper reports on the detailed characterisation of the K2-111 planetary system with K2, WASP, and ASAS-SN photometry as well as high-resolution spectroscopic data from HARPS-N and ESPRESSO. The host, K2-111, is confirmed to be a mildly evolved ($\log g=4.17$), iron-poor ([Fe/H]$=-0.46$), but alpha-enhanced ([$\alpha$/Fe]$=0.27$), chromospherically quiet, very old thick disc G2 star. A global fit, performed by using PyORBIT shows that the transiting planet, K2-111b, orbits with a period $P_b=5.3518\pm0.0004$ d, and has a planet radius of $1.82^{+0.11}_{-0.09}$ R$_\oplus$ and a mass of $5.29^{+0.76}_{-0.77}$ M$_\oplus$, resulting in a bulk density slightly lower than that of the Earth. The stellar chemical composition and the planet properties are consistent with K2-111b being a terrestrial planet with an iron core mass fraction lower than the Earth. We announce the existence of a second signal in the radial velocity data that we attribute to a non-transiting planet, K2-111c, with an orbital period of $15.6785\pm 0.0064$ days, orbiting in near-3:1 mean-motion resonance with the transiting planet, and a minimum planet mass of $11.3\pm1.1$ M$_\oplus$. Both planet signals are independently detected in the HARPS-N and ESPRESSO data when fitted separately. There are potentially more planets in this resonant system, but more well-sampled data are required to confirm their presence and physical parameters., Comment: Accepted for publication in MNRAS on 28 Sept 2020. Paper is 18 pages with an additional 12 pages of supplementary material. Data is available at https://vizier.u-strasbg.fr/viz-bin/VizieR?-source=J/MNRAS/499/5004

Published
2020

25. Effect of stellar activity on the high precision transit light curve

Author

Gwenaël Boué, Pedro Figueira, Mahmoudreza Oshagh, David Ehrenreich, Isabelle Boisse, Xavier Dumusque, Nader Haghighipour, Nuno C. Santos, Alexandre Santerne, 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 Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Sunspot, QC1-999, Astrophysics, Radius, Light curve, Signal, Wavelength, Amplitude, Planet, [SDU]Sciences of the Universe [physics], Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), Astrophysics::Earth and Planetary Astrophysics, Computer Science::Databases
Abstract

International audience; Stellar activity features such as spots and plages can create difficulties in determining planetary parameters through spectroscopic and photometric observations. The overlap of a transiting planet and a stellar spot, for instance, can produce anomalies in the transit light curve that may lead to inaccurate estimation of the transit duration, depth, and timing. Such inaccuracies can affect the precise derivation of the planet's radius. In this talk we will present the results of a quantitative study on the effects of stellar spots on high precision transit light curves. We show that spot anomalies can lead to the estimate of a planet radius that is 4% smaller than the real value. The effects on the transit duration can also be of the order of 4%, longer or shorter. Depending on the size and distribution of spots, anomalies can also produce transit timing variations with significant amplitudes. For instance, TTVs with signal amplitudes of 200 seconds can be produced by spots as large as the largest sunspot. Finally, we examine the impact of active regions on the transit depth measurements in different wavelengths, in order to probe the impact of this effect on transmission spectroscopy measurements. We show that significant (up to 10%) underestimation/overestimation of the planet-to-star radius ratio can be measured, especially in the short wavelength regime.

Published
2022

26. K2-79b and K2-222b: Mass Measurements of Two Small Exoplanets with Periods beyond 10 days that Overlap with Periodic Magnetic Activity Signals

Author

Chantanelle Nava, Mercedes López-Morales, Annelies Mortier, Li Zeng, Helen A. C. Giles, Allyson Bieryla, Andrew Vanderburg, Lars A. Buchhave, Ennio Poretti, Steven H. Saar, Xavier Dumusque, David W. Latham, David Charbonneau, Mario Damasso, Aldo S. Bonomo, Christophe Lovis, Andrew Collier Cameron, Jason D. Eastman, Alessandro Sozzetti, Rosario Cosentino, Marco Pedani, Francesco Pepe, Emilio Molinari, Dimitar Sasselov, Michel Mayor, Manu Stalport, Luca Malavolta, Ken Rice, Christopher A. Watson, A. F. Martinez Fiorenzano, Luca Di Fabrizio, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Nava, Chantanelle [0000-0001-8838-3883], López-Morales, Mercedes [0000-0003-3204-8183], Mortier, Annelies [0000-0001-7254-4363], Zeng, Li [0000-0003-1957-6635], Giles, Helen AC [0000-0001-6777-4797], Bieryla, Allyson [0000-0001-6637-5401], Vanderburg, Andrew [0000-0001-7246-5438], Buchhave, Lars A [0000-0003-1605-5666], Poretti, Ennio [0000-0003-1200-0473], Saar, Steven H [0000-0001-7032-8480], Dumusque, Xavier [0000-0002-9332-2011], Latham, David W [0000-0001-9911-7388], Charbonneau, David [0000-0002-9003-484X], Damasso, Mario [0000-0001-9984-4278], Bonomo, Aldo S [0000-0002-6177-198X], Eastman, Jason D [0000-0003-3773-5142], Sozzetti, Alessandro [0000-0002-7504-365X], Pedani, Marco [0000-0002-5752-6260], Molinari, Emilio [0000-0002-1742-7735], Sasselov, Dimitar [0000-0001-7014-1771], Mayor, Michel [0000-0002-9352-5935], Malavolta, Luca [0000-0002-6492-2085], Martinez Fiorenzano, AF [0000-0002-4272-4272], Apollo - University of Cambridge Repository, Nava, C [0000-0001-8838-3883], López-Morales, M [0000-0003-3204-8183], Mortier, A [0000-0001-7254-4363], Zeng, L [0000-0003-1957-6635], Giles, HAC [0000-0001-6777-4797], Bieryla, A [0000-0001-6637-5401], Vanderburg, A [0000-0001-7246-5438], Buchhave, LA [0000-0003-1605-5666], Poretti, E [0000-0003-1200-0473], Saar, SH [0000-0001-7032-8480], Dumusque, X [0000-0002-9332-2011], Latham, DW [0000-0001-9911-7388], Charbonneau, D [0000-0002-9003-484X], Damasso, M [0000-0001-9984-4278], Bonomo, AS [0000-0002-6177-198X], Eastman, JD [0000-0003-3773-5142], Sozzetti, A [0000-0002-7504-365X], Pedani, M [0000-0002-5752-6260], Molinari, E [0000-0002-1742-7735], Sasselov, D [0000-0001-7014-1771], Mayor, M [0000-0002-9352-5935], and Malavolta, L [0000-0002-6492-2085]

Subjects
MCC, Earth and Planetary Astrophysics (astro-ph.EP), The Solar System, Exoplanets, and Astrobiology, Exoplanet astronomy, FOS: Physical sciences, Astronomy and Astrophysics, 3rd-DAS, Stellar activity, QC Physics, Space and Planetary Science, astro-ph.EP, QB Astronomy, QC, Astrophysics - Earth and Planetary Astrophysics, QB
Abstract

We present mass and radius measurements of K2-79b and K2-222b, two transiting exoplanets orbiting active G-type stars. Their respective 10.99d and 15.39d orbital periods fall near periods of signals induced by stellar magnetic activity. The two signals might therefore interfere and lead to an inaccurate estimate of exoplanet mass. We present a method to mitigate these effects when radial velocity and activity indicator observations are available over multiple observing seasons and the orbital period of the exoplanet is known. We perform correlation and periodogram analyses on sub-sets composed of each target's two observing seasons, in addition to the full data sets. For both targets, these analyses reveal an optimal season with little to no interference at the orbital period of the known exoplanet. We make a confident mass detection of each exoplanet by confirming agreement between fits to the full radial velocity set and the optimal season. For K2-79b, we measure a mass of 11.8 $\pm$ 3.6 $M_{Earth}$ and a radius of 4.09 $\pm$ 0.17 $R_{Earth}$. For K2-222b, we measure a mass of 8.0 $\pm$ 1.8 $M_{Earth}$ and a radius of 2.35 $\pm$ 0.08 $R_{Earth}$. According to model predictions, K2-79b is a highly irradiated Uranus-analog and K2-222b hosts significant amounts of water ice. We also present an RV solution for a candidate second companion orbiting K2-222 at 147.5d., Comment: 33 pages, 17 figures, 13 tables

Published
2022
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27. Line-by-line velocity measurements, an outlier-resistant method for precision velocimetry

Author

Étienne Artigau, Charles Cadieux, Neil J. Cook, René Doyon, Thomas Vandal, Jean-François Donati, Claire Moutou, Xavier Delfosse, Pascal Fouqué, Eder Martioli, François Bouchy, Jasmine Parsons, Andres Carmona, Xavier Dumusque, Nicola Astudillo-Defru, Xavier Bonfils, Lucille Mignon, 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 ), 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)-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

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

We present a new algorithm for precision radial velocity (pRV) measurements, a line-by-line (LBL) approach designed to handle outlying spectral information in a simple but efficient manner. The effectiveness of the LBL method is demonstrated on two datasets, one obtained with SPIRou on Barnard's star, and the other with HARPS on Proxima Centauri. In the near-infrared, the LBL provides a framework for m/s-level accuracy in pRV measurements despite the challenges associated with telluric absorption and sky emission lines. We confirm with SPIRou measurements spanning 2.7 years that the candidate super-Earth on a 233-day orbit around Barnard's star is an artifact due to a combination of time-sampling and activity. The LBL analysis of the Proxima Centauri HARPS post-upgrade data alone easily recovers the Proxima b signal and also provides a 2-sigma detection of the recently confirmed 5-day Proxima d planet, but argues against the presence of the candidate Proxima c with a period of 1900 days. We provide evidence that the Proxima c signal is associated with small, unaccounted systematic effects affecting the HARPS-TERRA template matching RV extraction method for long-period signals. Finally, the LBL framework provides a very effective activity indicator, akin to the full width at half maximum derived from the cross-correlation function, from which we infer a rotation period of $92.1^{+4.2}_{-3.5}$ days for Proxima., Accepted for publication in AJ

Published
2022
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28. Kepler-102: Masses and Compositions for a Super-Earth and Sub-Neptune Orbiting an Active Star

Author

Casey L. Brinkman, James Cadman, Lauren Weiss, Eric Gaidos, Ken Rice, Daniel Huber, Zachary R. Claytor, Aldo S. Bonomo, Lars A. Buchhave, Andrew Collier Cameron, Rosario Cosentino, Xavier Dumusque, Aldo F. Martinez Fiorenzano, Adriano Ghedina, Avet Harutyunyan, Andrew Howard, Howard Isaacson, David W. Latham, Mercedes López-Morales, Luca Malavolta, Giuseppina Micela, Emilio Molinari, Francesco Pepe, David F. Philips, Ennio Poretti, Alessandro Sozzetti, Stéphane Udry, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
MCC, Earth and Planetary Astrophysics (astro-ph.EP), astro-ph.SR, FOS: Physical sciences, Astronomy and Astrophysics, 3rd-DAS, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, astro-ph.EP, QB Astronomy, QC, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics, QB
Abstract

Radial velocity (RV) measurements of transiting multiplanet systems allow us to understand the densities and compositions of planets unlike those in the Solar System. Kepler-102, which consists of 5 tightly packed transiting planets, is a particularly interesting system since it includes a super-Earth (Kepler-102d) and a sub-Neptune-sized planet (Kepler-102e) for which masses can be measured using radial velocities. Previous work found a high density for Kepler-102d, suggesting a composition similar to that of Mercury, while Kepler-102e was found to have a density typical of sub-Neptune size planets; however, Kepler-102 is an active star, which can interfere with RV mass measurements. To better measure the mass of these two planets, we obtained 111 new RVs using Keck/HIRES and TNG/HARPS-N and modeled Kepler-102's activity using quasi-periodic Gaussian Process Regression. For Kepler-102d, we report a mass upper limit of M$_{d} < $5.3 M$_{\oplus}$ [95\% confidence], a best-fit mass of M$_{d}$=2.5 $\pm$ 1.4 M$_{\oplus}$, and a density of $\rho_{d}$=5.6 $\pm$ 3.2 g/cm$^{3}$ which is consistent with a rocky composition similar in density to the Earth. For Kepler-102e we report a mass of M$_{e}$=4.7 $\pm$ 1.7 M$_{\oplus}$ and a density of $\rho_{e}$=1.8 $\pm$ 0.7 g/cm$^{3}$. These measurements suggest that Kepler-102e has a rocky core with a thick gaseous envelope comprising 2-4% of the planet mass and 16-50% of its radius. Our study is yet another demonstration that accounting for stellar activity in stars with clear rotation signals can yield more accurate planet masses, enabling a more realistic interpretation of planet interiors., Comment: Accepted to AJ 11/08/2022

Published
2022
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29. HD 207897 b:A dense sub-Neptune transiting a nearby and bright K-type star

Author

Andrew W. Mayo, Jorge Lillo-Box, George R. Ricker, C. Moutou, Stephen R. Kane, René Tronsgaard, Ashley Chontos, Allyson Bieryla, Karen A. Collins, Nicola Astudillo-Defru, Luc Arnold, Rafael Luque, Andrew W. Howard, Xavier Dumusque, S. G. Sousa, V. Bourrier, Erik Petigura, Joshua N. Winn, Magali Deleuil, Lauren M. Weiss, Enric Palle, Nuno C. Santos, Steven Giacalone, J. Rey, Damien Ségransan, Courtney D. Dressing, Paul A. Dalba, Arpita Roy, Jack Lubin, Sara Seager, Corey Beard, Natalie M. Batalha, Daniel Huber, C. E. Brasseur, T. Lopez, Howard Isaacson, Teo Mocnik, Jason D. Eastman, Peter Tenenbaum, N. Heidari, Michelle L. Hill, P. Cortés-Zuleta, O. Mousis, E. Delgado Mena, Diana Dragomir, D. W. Latham, François Bouchy, Aida Behmard, David Ehrenreich, P. A. Strøm, Fei Dai, F. Vakili, T. Forveille, Tansu Daylan, R. Vanderspek, Keivan G. Stassun, Alexandre Santerne, Melissa J. Hobson, X. Bonfils, Benjamin J. Fulton, G. Montagnier, M. Stalport, Francesco Pepe, Lars A. Buchhave, Flavien Kiefer, Nicholas Scarsdale, Lee J. Rosenthal, Vardan Adibekyan, Paul Robertson, Olivier Demangeon, J. M. Jenkins, A. Carmona, Nematollah Riazi, Stéphane Udry, Rodrigo F. Díaz, N. C. Hara, G. Gaisne, Thomas Barclay, Tara Fetherolf, X. Delfosse, L. Mignon, Sergio Hoyer, B. Courcol, J. Orell-Mique, S. Borgniet, Guillaume Hébrard, Ryan A. Rubenzahl, Lea A. Hirsch, S. Dalal, Ian J. M. Crossfield, Joseph M. Akana Murphy, L. Acuna, Isabelle Boisse, 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), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), 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), Geneva Observatory, Université de Genève = University of Geneva (UNIGE), European Southern Observatory (ESO), 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), Departamento de Matemática y Fı́sica Aplicadas [Concepcion] (DMFA), Universidad Católica de la Santísima Concepción (UCSC), University of St Andrews [Scotland], Faculdade de Ciências [Lisboa], Universidade de Lisboa = University of Lisbon (ULISBOA), SwRI Planetary Science Directorate [Boulder], Southwest Research Institute [Boulder] (SwRI), 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, NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Observatoire Astronomique de l'Université de Genève (ObsGE), National Space Institute [Lyngby] (DTU Space), Danmarks Tekniske Universitet = Technical University of Denmark (DTU), SETI Institute, Instituto de Astrofísica e Ciências do Espaço (IASTRO), MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology (MIT), Department of Astronomy, University of California, Genome Sequencing Center, University of Washington School of Medicine, Universidad de Chile = University of Chile [Santiago] (UCHILE), Departamento de Quimica Inorganica e Ingenieria Quimica (Cordoba, Spain), Universidad de Córdoba = University of Córdoba [Córdoba], Peoples Friendship University of Russia [RUDN University] (RUDN), Center for Astrophysics (emeritus), Harvard-Smithsonian, Cambridge, MA, USA, Institut de recherche en astrophysique et planétologie (IRAP), 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), Institut de Recherche pour le Développement (IRD)-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)-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), Laboratoire de Didactique André Revuz (LDAR (EA_4434)), Université d'Artois (UA)-Université Paris Diderot - Paris 7 (UPD7)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Instituto de Astrofisica de Canarias (IAC), Universidad de La Laguna [Tenerife - SP] (ULL), Vanderbilt University [Nashville], SLAC National Accelerator Laboratory (SLAC), Stanford University, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Peyton Hall, Clarient Pathology Services, Partenaires INRAE, Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), University of Geneva [Switzerland], Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, Instituto de Astronomía y Física del Espacio [Buenos Aires] (IAFE), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad de Buenos Aires [Buenos Aires] (UBA), IFP Energies nouvelles (IFPEN), Center for Space Research [Cambridge] (CSR), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), 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), and ANR-18-CE31-0019,SPlaSH,Recherche de planètes habitables avec SPIRou(2018)

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 010308 nuclear & particles physics, Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, Planetary system, Star (graph theory), 01 natural sciences, Exoplanet, Radial velocity, 13. Climate action, Space and Planetary Science, Planet, Neptune, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], education, 010303 astronomy & astrophysics, QB, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the discovery and characterization of a transiting sub-Neptune orbiting with a 16.20 day period around a nearby (28 pc) and bright(V=8.37) K0V star HD207897 (TOI-1611). This discovery is based on photometric measurements from the Transiting Exoplanet Survey Satellite(TESS) mission and radial velocity (RV) observations from the SOPHIE, Automated Planet Finder (APF) and HIRES high precision spectrographs. We used EXOFASTv2 for simultaneously modeling the parameters of the planet and its host star, combining photometric and RV data to determine the planetary system parameters. We show that the planet has a radius of 2.50+/-0.08 RE and a mass of either 14.4+/-1.6 ME or 15.9+/-1.6 ME with nearly equal probability; the two solutions correspond to two possibilities for the stellar activity period. Hence, the density is either 5.1+/-0.7 g cm^-3 or 5.5^{+0.8}_{-0.7} g cm^-3, making it one of the relatively rare dense sub-Neptunes. The existence of such a dense planet at only 0.12 AU from its host star is unusual in the currently observed sub-Neptune (2, Comment: 18 pages, 12 figures, 6 tables; accepted for publication in the A&A journal; comments welcome

Published
2022

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

Author

Andrés Jordán, Sara Seager, Brett C. Addison, Maximilian N. Günther, Monika Lendl, Jack Okumura, Jorge Lillo-Box, Jon M. Jenkins, Roland Vanderspek, C. G. Tinney, Benjamin J. Fulton, Peter J. Wheatley, Erik A. Petigura, Beth A. Henderson, C. Stibbard, P. Figueira, Rafael Brahm, Eric L. N. Jensen, Michael Reefe, Cesar Briceno, Chris Stockdale, S. Hojjatpanah, Farisa Y. Morales, Alexis M. S. Smith, Caroline Dorn, Thomas Henning, Vardan Adibekyan, George W. King, Lauren M. Weiss, David R. Ciardi, Howard Isaacson, Richard P. Schwarz, Thomas Barclay, Stephen R. Kane, Keivan G. Stassun, David W. Latham, Malcolm Fridlund, Jack S. Acton, Ravit Helled, Sharon X. Wang, John Berberian, Joseph D. Twicken, J. F. Otegi, David R. Anderson, Sarah L. Casewell, Elise Furlan, Elisabeth Matthews, Johanna Teske, Rodrigo F. Díaz, Samuel Gill, Daniel Bayliss, Ian Crossfield, Peter Plavchan, Matthew W. Mengel, Joshua E. Schlieder, John F. Kielkopf, Stéphane Udry, E. Delgado Mena, H. P. Osborn, Avi Shporer, R. Cloutier, J. Villasenor, Duncan J. Wright, E. Gaidos, A. Osborn, K. I. Collins, Angelle Tanner, Nicholas M. Law, Björn Benneke, Joshua N. Winn, Fei Dai, Nicholas J. Scott, Erica J. Gonzales, Courtney D. Dressing, Sarah Ballard, Don Pollacco, Coel Hellier, Michael R. Goad, David J. Armstrong, Varoujan Gorjian, Paula Sarkis, Richard C. Kidwell, F. Zohrabi, Nuno C. Santos, David Barrado, Matthew R. Burleigh, Sergio Hoyer, Claire Geneser, Christopher J. Burke, Richard G. West, James McCormac, P. A. Strøm, Daniel Huber, Aleisha Hogan, Paul Robertson, Natalie M. Batalha, Edward M. Bryant, Liam Raynard, Karen A. Collins, Robert A. Wittenmyer, Mark E. Rose, Rachel A. Matson, Steve B. Howell, James S. Jenkins, Jose I. Vines, S. C. C. Barros, Néstor Espinoza, B. Cale, Andrew W. Howard, Diana Dragomir, Alexandre Santerne, M. Lund, Olivier Demangeon, Brendan P. Bowler, Benjamin F. Cooke, Xavier Dumusque, Andrew W. Mann, Hui Zhang, Carl Ziegler, Arpita Roy, Rosanna H. Tilbrook, Sérgio F. Sousa, George R. Ricker, Jonathan Horner, Elisa V. Quintana, Thiam-Guan Tan, Louise D. Nielsen, François Bouchy, University of New South Wales [Sydney] (UNSW), McDonald Observatory, University of Texas at Austin [Austin], Leiden Observatory [Leiden], Universiteit Leiden, Chalmers University of Technology [Gothenburg, Sweden], NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Instituto de Astrofísica e Ciências do Espaço (IASTRO), Center for Space Research [Cambridge] (CSR), Massachusetts Institute of Technology (MIT), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Département de Physique [Montréal], Université de Montréal (UdeM), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Leicester], University of Leicester, Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), Optimisation - Système - Energie (GEPEA-OSE), Laboratoire de génie des procédés - environnement - agroalimentaire (GEPEA), Institut Universitaire de Technologie - Nantes (IUT Nantes), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut Universitaire de Technologie Saint-Nazaire (IUT Saint-Nazaire), Université de Nantes (UN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut Universitaire de Technologie - La Roche-sur-Yon (IUT La Roche-sur-Yon), Université de Nantes (UN)-Institut Universitaire de Technologie - Nantes (IUT Nantes), Université de Nantes (UN), Institut für Virologie, Philipps University, MIT Kavli Institute for Astrophysics and Space Research, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Department of Geology and Geophysics [Mānoa], University of Hawai‘i [Mānoa] (UHM), Universität Zürich [Zürich] = University of Zurich (UZH), Department of Earth and Planetary Science [UC Berkeley] (EPS), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Universidad de Chile = University of Chile [Santiago] (UCHILE), Pontificia Universidad Católica de Chile (UC), University of Louisville, Austrian Academy of Sciences (OeAW), Lund University [Lund], University of Warwick [Coventry], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), German Aerospace Center (DLR), Swiss Bee Research Centre, Centre for Medical Image Computing (CMIC), and University College of London [London] (UCL)

Subjects
(TOI-431, planets and satellites: detection, Fundamental Parameters, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], (TOI-431, TIC 31374837), FOS: Physical sciences, Individual, Astrophysics, Q1, 01 natural sciences, Neptune, Planet, QB460, 0103 physical sciences, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, QB600, QC, 0105 earth and related environmental sciences, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Super-Earth, Astronomy and Astrophysics, Planets and Satellites, Radius, Light curve, Exoplanet, Radial velocity, Photometry (astronomy), Detection, 13. Climate action, Space and Planetary Science, planets and satellites: individual: (TOI-431, TIC 31374837), Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the bright (V$_{mag} = 9.12$), multi-planet system TOI-431, characterised with photometry and radial velocities. We estimate the stellar rotation period to be $30.5 \pm 0.7$ days using archival photometry and radial velocities. TOI-431b is a super-Earth with a period of 0.49 days, a radius of 1.28 $\pm$ 0.04 R$_{\oplus}$, a mass of $3.07 \pm 0.35$ M$_{\oplus}$, and a density of $8.0 \pm 1.0$ g cm$^{-3}$; TOI-431d is a sub-Neptune with a period of 12.46 days, a radius of $3.29 \pm 0.09$ R$_{\oplus}$, a mass of $9.90^{+1.53}_{-1.49}$ M$_{\oplus}$, and a density of $1.36 \pm 0.25$ g cm$^{-3}$. We find a third planet, TOI-431c, in the HARPS radial velocity data, but it is not seen to transit in the TESS light curves. It has an $M \sin i$ of $2.83^{+0.41}_{-0.34}$ M$_{\oplus}$, and a period of 4.85 days. TOI-431d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterisation, while the super-Earth TOI-431b may be a stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431b is a prime TESS discovery for the study of rocky planet phase curves., Comment: 21 pages, 11 figures, 3 appendices, accepted for publication in MNRAS

Published
2021

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

Author

Petr Kabath, K. I. Collins, Florian Rodler, Christopher Stockdale, Sara Seager, T. Lopez, S. Hojjatpanah, Steve B. Howell, S. Sabotta, Nuno C. Santos, David Barrado, Enric Palle, Jan Subjak, M. Esposito, John P. Doty, Rafael Luque, Artyom Aguichine, Karen A. Collins, Olivier Demangeon, Vincent Van Eylen, J. R. De Medeiros, M. Fridlund, N. Scott, Susan E. Mullally, E. Goffo, J. F. Otegi, D. W. Latham, Oscar Barragán, Jon M. Jenkins, Rodrigo F. Díaz, L. M. Serrano, Stéphane Udry, P. Figueira, A. P. Hatzes, Vardan Adibekyan, Davide Gandolfi, P. Cortés-Zuleta, W. Fong, J. Cabrera, Peter J. Wheatley, Seth Redfield, Sascha Grziwa, A. Santerne, Benjamin F. Cooke, Sergio Hoyer, L. Acuña, Daniel Bayliss, J. D. Twicken, S. G. Sousa, A. Osborn, Joshua N. Winn, P. A. Strøm, Hans J. Deeg, E. Delgado Mena, H. P. Osborn, William D. Cochran, Rachel A. Matson, Elise Furlan, Jorge Lillo-Box, P. T. Boyd, John H. Livingston, I. C. Leão, James A. G. Jackman, Edward M. Bryant, François Bouchy, Magali Deleuil, O. Mousis, Jose-Manuel Almenara, Carina M. Persson, Judith Korth, Roland Vanderspek, Louise D. Nielsen, B. L. Canto Martins, David J. Armstrong, Eric L. N. Jensen, Emil Knudstrup, D. A. Yahalomi, Jeffrey C. Smith, S. C. C. Barros, Xavier Dumusque, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Department of Brain and Behavioural Sciences, University of Pavia, European Southern Observatory (ESO), Instituto de Astrofísica e Ciências do Espaço (IASTRO), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto, Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Groupe de Recherche en Astronomie et Astrophysique du Languedoc (GRAAL), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astronomía y Física del Espacio [Buenos Aires] (IAFE), Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad de Buenos Aires [Buenos Aires] (UBA), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Center for Space Research [Cambridge] (CSR), Massachusetts Institute of Technology (MIT), University of Warwick [Coventry], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Physics [Coventry], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Institute for Marine and Antarctic Studies [Horbat] (IMAS), University of Tasmania [Hobart, Australia] (UTAS), PSE-ENV/SEDRE/LETIS, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), European Southern Observatory [Santiago] (ESO), Thüringer Landessternwarte Tautenburg (TLS), Astronomical Institute of the Czech Academy of Sciences (ASU / CAS), Czech Academy of Sciences [Prague] (CAS), Universidad de Córdoba [Cordoba], Instituto de Astrofisica de Canarias (IAC), Wesleyan University, Departamento de Física e Astronomia [Porto] (DFA/FCUP), Faculdade de Ciências da Universidade do Porto (FCUP), Universidade do Porto-Universidade do Porto, Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Pavia = University of Pavia (UNIPV), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universidade do Porto = University of Porto, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Université de Genève = University of Geneva (UNIGE), Institute for Marine and Antarctic Studies [Hobart] (IMAS), Laboratoire d'étude et de recherche sur les transferts et les interactions dans les sous-sols (IRSN/PSE-ENV/SEDRE/LETIS), Service des déchets radioactifs et des transferts dans la géosphère (IRSN/PSE-ENV/SEDRE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Universidad de Córdoba = University of Córdoba [Córdoba], and Universidade do Porto = University of Porto-Universidade do Porto = University of Porto

Subjects
Dwarf star, Fundamental Parameters, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Individual, Astrophysics, Photometric, planets and satellites: individual: TYC 8897-01263-1, 01 natural sciences, techniques: photometric, Planet, Neptune, 0103 physical sciences, techniques: radial velocities, Radial Velocities, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, TYC 8897-01263-1, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy and Astrophysics, Planets and Satellites, Radius, Planetary system, Stars, Exoplanet, Techniques, Radial velocity, 13. Climate action, Space and Planetary Science, echniques: photometric, stars: fundamental parameters, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract

In this paper we report the discovery of TOI-220 $b$, a new sub-Neptune detected by the Transiting Exoplanet Survey Satellite (TESS) and confirmed by radial velocity follow-up observations with the HARPS spectrograph. Based on the combined analysis of TESS transit photometry and high precision radial velocity measurements we estimate a planetary mass of 13.8 $\pm$ 1.0 M$_{Earth}$ and radius of 3.03 $\pm$ 0.15 R$_{Earth}$, implying a bulk density of 2.73 $\pm$ 0.47 $\textrm{g cm}^{-3}$. TOI-220 $b$ orbits a relative bright (V=10.4) and old (10.1$\pm$1.4 Gyr) K dwarf star with a period of $\sim$10.69 d. Thus, TOI-220 $b$ is a new warm sub-Neptune with very precise mass and radius determinations. A Bayesian analysis of the TOI-220 $b$ internal structure indicates that due to the strong irradiation it receives, the low density of this planet could be explained with a steam atmosphere in radiative-convective equilibrium and a supercritical water layer on top of a differentiated interior made of a silicate mantle and a small iron core., Comment: Accepted for publication in MNRAS

Published
2021

32. Chromatic drift of the Espresso Fabry-Pérot etalon

Author

Tobias M. Schmidt, Bruno Chazelas, Christophe Lovis, Xavier Dumusque, François Bouchy, Francesco Pepe, Pedro Figueira, and Danuta Sosnowska

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, Astrophysics::Instrumentation and Methods for Astrophysics, Physics::Optics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics - Earth and Planetary Astrophysics
Abstract

In the last decade, white-light illuminated Fabry-P\'erot interferometers wave been established as a widely used, relatively simple, reliable, and cost-effective way to precisely calibrate high-resolution echelle spectrographs. However, Terrien et al. (2021) recently reported a chromatic drift of the Fabry-P\'erot interferometer installed at the Habitable-zone Planet Finder spectrograph. In particular, they found that the variation of the etalon effective gap size is not achromatic as usually assumed but in fact depends on wavelength. Here, we present a similar study of the Espresso Fabry-P\'erot interferometer. Using daily calibrations spanning a period of over 2.5 years, we also find clear evidence for a chromatic drift with an amplitude of a few cm/s per day that has a characteristic, quasi-oscillatory dependence on wavelength. We conclude that this effect is probably caused by an aging of the dielectric mirror coatings and expect that similar chromatic drifts might affect all Fabry-P\'erot interferometers used for calibration of astronomical spectrographs. However, we also demonstrate that the chromatic drift can be measured and in principle corrected using only standard calibrations based on hollow cathode lamp spectra., Comment: 8 pages, 3 figures; accepted for publication in A&A

Published
2022

33. Testing whether a signal is strictly periodic. Application to disentangling planets and stellar activity in radial velocities

Author

J.-B. Delisle, Xavier Dumusque, Nathan Hara, and N. Unger

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Phase (waves), G.3, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Signal, Stability (probability), Radial velocity, Periodic function, Amplitude, 62P35, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, Solar rotation, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

Searches for periodicity in time series are often done with models of periodic signals, whose statistical significance is assessed via false alarm probabilities or Bayes factors. However, a statistically significant periodic model might not originate from a strictly periodic source. In astronomy in particular, one expects transient signals that show periodicity for a certain amount of time before vanishing. This situation is encountered for instance in the search for planets in radial velocity data. While planetary signals are expected to have a stable phase, amplitude and frequency - except when strong planet-planet interactions are present - signals induced by stellar activity will typically not exhibit the same stability. In the present article, we explore the use of periodic functions multiplied by time windows to diagnose whether an apparently periodic signal is truly so. We suggest diagnostics to check whether a signal is consistently present in the time series, and has a stable phase, amplitude and period. The tests are expressed both in a periodogram and Bayesian framework. Our methods are applied to the Solar HARPS-N data as well as HD 215152, HD 69830 and HD 13808. We find that (i) the HARPS-N Solar data exhibits signals at the Solar rotation period and its first harmonic ($\sim$ 13.4 days). The frequency and phase of the 13.4 days signal appear constant within the estimation uncertainties, but its amplitude presents significant variations which can be mapped to activity levels. (ii) as previously reported, we find four, three and two planets orbiting HD 215152, HD 69830 and HD 13808., Accepted for publication in Astronomy & Astrophysics

Published
2021

34. Six transiting planets and a chain of Laplace resonances in TOI-178

Author

A. Leleu, Nathan Hara, Rosanna H. Tilbrook, Matthew J. Hooton, Jack S. Acton, Giuseppina Micela, Heike Rauer, Francisco J. Pozuelos, Xavier Dumusque, Michael R. Goad, T. Bárczy, Andrew Collier Cameron, Francesco Pepe, G. Lo Curto, Rafael Rebolo, Juan Cabrera, Pedro Figueira, M. Buder, Willy Benz, Romain Allart, Oliver Turner, Enric Palle, Alexis M. S. Smith, Ignasi Ribas, F. Ratti, M. Steller, Richard G. West, James McCormac, A. Lecavelier des Etangs, Alexandre C. M. Correia, Daniel Sebastian, S. G. Sousa, Emmanuel Jehin, Mathias Beck, J. Schneider, François Bouchy, Baptiste Lavie, J.-B. Delisle, Liam Raynard, Roberto Ragazzoni, K. Lam, H. Venus, Kate Gudrun Isaak, Roi Alonso, C. Murray, Laetitia Delrez, Martti H. Kristiansen, Mario Damasso, A. Bonfanti, David Ehrenreich, Stéphane Udry, Samuel Gill, Sergio Hoyer, Lionel Garcia, V. Adibekyan, Carina M. Persson, Maximiliano Moyano, Beth A. Henderson, Giampaolo Piotto, Andrés Jordán, Samantha Thompson, Alexis Brandeker, Elsa Ducrot, Daniel Angerhausen, Nuno C. Santos, David Barrado, Xavier Bonfils, Vincent Bourrier, F. Verrecchia, Monika Lendl, Andrea Mehner, C. Broeg, M. R. Zapatero Osorio, Matthew R. Burleigh, D. Futyan, Damien Ségransan, Amaury H. M. J. Triaud, Mahmoudreza Oshagh, C. Allende Prieto, J. Asquier, B. O. Demory, Philippe Robutel, C. Corral Van Damme, Nicola Rando, Malcolm Fridlund, Gisbert Peter, Roland Ottensamer, Alessandro Sozzetti, Paolo Molaro, James S. Jenkins, Melvyn B. Davies, Jorge Lillo-Box, S. Chamberlain, Thomas Beck, P. Di Marcantonio, Carlos Martins, Maximilian N. Günther, Daniel Bayliss, Jacques Laskar, Peter J. Wheatley, P. P. Pedersen, Nicolas Thomas, Nicholas A. Walton, Göran Olofsson, Marko Sestovic, David R. Anderson, Artem Burdanov, Kevin Heng, Manuel Guedel, Jose I. Vines, A. García Muñoz, Edward Gillen, Valérie Van Grootel, T. G. Wilson, Michaël Gillon, Olivier Demangeon, D. Wolter, Demetrio Magrin, G. Polenta, G. Anglada Escudé, Stefano Cristiani, J. Haldemann, László L. Kiss, H. P. Osborn, Valerio Nascimbeni, Aleisha Hogan, Ennio Poretti, Pierre F. L. Maxted, S. C. C. Barros, G. Boué, Sébastien Charnoz, Benjamin F. Cooke, Nicolas Billot, C. Reimers, Don Pollacco, Gaetano Scandariato, Luca Fossati, Douglas R. Alves, J. I. González Hernández, Edward M. Bryant, Anders Erikson, Nelson J. Nunes, Wolfgang Baumjohann, Yann Alibert, A. Suárez Mascareño, Antoine Simon, Gy. M. Szabó, C. Lovis, Magali Deleuil, Andrea Fortier, Isabella Pagano, A. Bekkelien, G. Di Persio, Didier Queloz, Davide Gandolfi, Centre Hospitalier Régional Universitaire [Lille] (CHRU Lille), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), 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), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), 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, ITA, USA, GBR, FRA, DEU, AUT, BEL, CHL, DNK, NLD, PRT, SWE, CHE, HUN, Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université de Genève (UNIGE), 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), Swiss National Science Foundation, Agence Nationale de la Recherche (France), Science and Technology Facilities Council (UK), Belgian Science Policy Office, Université de Liège, Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Generalitat de Catalunya, Fundação para a Ciência e a Tecnologia (Portugal), Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Alvarez, M. [0000-0002-6786-2620], Carrasco Martínez, J. M. [0000-0002-3029-5853], 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
Brightness, planets and satellites: detection, Laplace resonance, 010504 meteorology & atmospheric sciences, spectroscopic techniques, planets and satellites: dynamical evolution and stability, Astrophysics, 01 natural sciences, Transits, spectroscopic [Techniques], techniques: photometric, Planet, QB460, QB Astronomy, 010303 astronomy & astrophysics, planets and satellites dynamical evolution and stability, QC, Institut für Optische Sensorsysteme, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Laplace transform, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, photmetric [Techniques], 3rd-DAS, dynamical evolution and stability [Planets and satellites], planets and satellites detection, Astrophysics::Earth and Planetary Astrophysics, Extrasolare Planeten und Atmosphären, Techniques: photmetric, FOS: Physical sciences, Context (language use), SPECULOOS, Earth radius, Mean-motion resonance, 0103 physical sciences, Celestial mechanics, CHEOPS, QB600, 0105 earth and related environmental sciences, photometric techniques, TESS, Scattering, Leitungsbereich PF, photometric [Techniques], Astronomy and Astrophysics, celestial mechanics, 620 Engineering, detection [Planets and satellites], QC Physics, 13. Climate action, Space and Planetary Science, NGTS, Planetare Sensorsysteme, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Event (particle physics), techniques: spectroscopic, QB799, Planets and satellites: Detection, Planets and satellites: Dynamical evolution and stability, Techniques: Photometric, Techniques: Spectroscopic, Astrophysics - Earth and Planetary Astrophysics
Abstract

Leleu, A., et al., Determining the architecture of multi-planetary systems is one of the cornerstones of understanding planet formation and evolution. Resonant systems are especially important as the fragility of their orbital configuration ensures that no significant scattering or collisional event has taken place since the earliest formation phase when the parent protoplanetary disc was still present. In this context, TOI-178 has been the subject of particular attention since the first TESS observations hinted at the possible presence of a near 2:3:3 resonant chain. Here we report the results of observations from CHEOPS, ESPRESSO, NGTS, and SPECULOOS with the aim of deciphering the peculiar orbital architecture of the system. We show that TOI-178 harbours at least six planets in the super-Earth to mini-Neptune regimes, with radii ranging from 1.152to 2.87Earth radii and periods of 1.91, 3.24, 6.56, 9.96, 15.23, and 20.71 days. All planets but the innermost one form a 2:4:6:9:12 chain of Laplace resonances, and the planetary densities show important variations from planet to planet, jumping from 1.02to 0.177times the Earth's density between planets c and d. Using Bayesian interior structure retrieval models, we show that the amount of gas in the planets does not vary in a monotonous way, contrary to what one would expect from simple formation and evolution models and unlike other known systems in a chain of Laplace resonances. The brightness of TOI-178 (H = 8.76 mag, J = 9.37 mag, V = 11.95 mag) allows for a precise characterisation of its orbital architecture as well as of the physical nature of the six presently known transiting planets it harbours. The peculiar orbital configuration and the diversity in average density among the planets in the system will enable the study of interior planetary structures and atmospheric evolution, providing important clues on the formation of super-Earths and mini-Neptunes., The authors acknowledge support from the Swiss NCCR PlanetS and the Swiss National Science Foundation. Y.A. and M.J.H. acknowledge the support of the Swiss National Fund under grant 200020_172746. A.C.C. and T.W. acknowledge support from STFC consolidated grant number ST/M001296/1. This work was granted access to the HPC resources of MesoPSL financed by the Region Ile de France and the project Equip@Meso (reference ANR-10-EQPX-29-01) of the programme Investissements d’Avenir supervised by the Agence Nationale pour la Recherche. SH acknowledges CNES funding through the grant 837319. Based on data collected under the NGTS project at the ESO La Silla Paranal Observatory. The NGTS facility is operated by the consortium institutes with support from the UK Science and Technology Facilities Council (STFC) project ST/M001962/1. The Belgian participation to CHEOPS has been supported by the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Program, and by the University of Liège through an ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. V.A. acknowledges the support from FCT through Investigador FCT contract nr. IF/00650/2015/CP1273/CT0001. We acknowledge support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grants ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, PGC2018-098153-B-C33, PGC2018-098153-B-C31, ESP2017-87676-C5-1-R, MDM-2017-0737 Unidad de Excelencia “María de Maeztu”- Centro de Astrobiología (INTA-CSIC), as well as the support of the Generalitat de Catalunya/CERCA programme. The MOC activities have been supported by the ESA contract No. 4000124370. S.C.C.B. acknowledges support from FCT through FCT contracts nr. IF/01312/2014/CP1215/CT0004. X.B., S.C., D.G., M.F. and J.L. acknowledge their role as ESA-appointed CHEOPS science team members. ABr was supported by the SNSA. A.C. acknowledges support by CFisUC projects (UIDB/04564/2020 and UIDP/04564/2020), GRAVITY (PTDC/FIS-AST/7002/2020), ENGAGE SKA (POCI-01-0145-FEDER-022217), and PHOBOS (POCI-01-0145-FEDER-029932), funded by COMPETE 2020 and FCT, Portugal. This work was supported by FCT - Fundaçãopara a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 - Programa OperacionalCompetitividade e Internacionalização by these grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020; PTDC/FIS-AST/32113/2017 and POCI-01-0145-FEDER- 032113; PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953; PTDC/FIS-AST/28987/2017 and POCI-01-0145-FEDER-028987. O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through FCT. B.-O.D. acknowledges support from the Swiss National Science Foundation (PP00P2-190080). M.F. and C.M.P. gratefully acknowledgethe support of the Swedish National Space Agency (DNR 65/19, 174/18). D.G. gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 “Gaseousor rocky? Unveiling the nature of small worlds”. E.G. gratefully acknowledges support from the David and Claudia Harding Foundation in the form of a WintonExoplanet Fellowship. M.G. is an F.R.S.-FNRS Senior Research Associate. J.I.G.H. acknowledges financial support from Spanish Ministry of Science and Innovation (MICINN) under the 2013 Ramón y Cajal programme RYC-2013-14875. J.I.G.H., A.S.M., R.R., and C.A.P. acknowledge financial support from the Spanish MICINN AYA2017-86389-P. A.S.M. acknowledges financial support from the Spanish Ministry of Science and Innovation (MICINN) under the 2019 Juan de la Cierva Programme. MNG ackowledges support from the MIT Kavli Institute as a Juan Carlos Torres Fellow. J.H. acknowledges the support of the Swiss National Fund under grant 200020_172746. KGI is the ESA CHEOPS Project Scientist and is responsible for the ESA CHEOPS Guest Observers Programme.She does not participate in, or contribute to, the definition of the Guaranteed Time Programme of the CHEOPS mission through which observations described in this paper have been taken, nor to any aspect of target selection forthe programme. J.S.J. acknowledges support by FONDECYT grant 1201371, and partial support from CONICYT project Basal AFB-170002. A.J. acknowledges support from ANID - Millennium Science Initiative - ICN12_009 and from FONDECYT project 1171208. P.M. acknowledges support from STFC research grant number ST/M001040/1. N.J.N is supported by the contract and exploratory project IF/00852/2015, and projects UID/FIS/04434/2019, PTDC/FIS-OUT/29048/2017, COMPETE2020: POCI-01-0145-FEDER-028987 & FCT: PTDC/FIS-AST/28987/2017. N.J.N is supported by the contract and exploratory project IF/00852/2015, and project PTDC/FIS-OUT/29048/2017. This work was also partially supported by a grant from the Simons Foundation (PI Queloz, grant number 327127). Acknowledges support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grant PGC2018-098153-B- C33, as well as the support of the Generalitat de Catalunya/CERCA programme. S.G.S. acknowledges support from FCT through FCT contract nr. CEECIND/00826/2018 and POPH/FSE (EC). This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This project has been supported by the Hungarian National Research, Development and Innovation Office (NKFIH) grants GINOP-2.3.2-15-2016-00003, K-119517, K-125015, and the City of Szombathely under Agreement No. 67.177-21/2016. This research received funding from the MERAC foundation, from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement no 803193/ BEBOP, and from the Science and Technology Facilites Council (STFC, grant no ST/S00193X/1). V.V.G. is an F.R.S-FNRS Research Associate. J.I.V. acknowledges support of CONICYT-PFCHA/Doctorado Nacional-21191829. M. R. Z. O. acknowledges financial support from projects AYA2016-79425-C3-2-P and PID2019-109522GB-C51 from the Spanish Ministry of Science, Innovation and Universities.

Published
2021

35. An unusually low density ultra-short period super-Earth and three mini-Neptunes around the old star TOI-561

Author

L. Borsato, T. G. Wilson, Joshua N. Winn, David F. Phillips, F. Lienhard, Stéphane Udry, L. Di Fabrizio, Ken Rice, Emilio Molinari, Jon M. Jenkins, Domenico Nardiello, Giuseppina Micela, Mario Damasso, Aldo S. Bonomo, Christopher A. Watson, Alessandro Sozzetti, Matteo Pinamonti, G. Lacedelli, Giampaolo Piotto, Mercedes López-Morales, Ennio Poretti, Xavier Dumusque, George R. Ricker, C. Lovis, Annelies Mortier, I. Pagano, G. Scandariato, A. Collier Cameron, Valerio Nascimbeni, Dimitar Sasselov, M. Stalport, Rosario Cosentino, Adriano Ghedina, Luca Malavolta, Francesco Pepe, David W. Latham, Lars A. Buchhave, Ararat Harutyunyan, Gloria Andreuzzi, A. F. Martinez Fiorenzano, David Charbonneau, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, 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), Mortier, Annelies [0000-0001-7254-4363], and Apollo - University of Cambridge Repository

Subjects
planets and satellites: detection, astro-ph.SR, 010504 meteorology & atmospheric sciences, stars: individual: TOI-561 (TIC 377064495, FOS: Physical sciences, 01 natural sciences, techniques: photometric, 0103 physical sciences, techniques: radial velocities, Low density, media_common.cataloged_instance, composition [Plants and satellites], QB Astronomy, European union, composition [planets and satellites], photometric – [Techniques], 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QC, 0105 earth and related environmental sciences, media_common, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Gaia DR2 3850421005290172416), radial velocities [Techniques], European research, photometric [Techniques], planets and satellites: composition, Astronomy and Astrophysics, DAS, individual: TOI-561 (TIC 377064495 [star], stars: individual: TOI-561 (TIC 377064495, Gaia DR2 3850421005290172416), detection [Planets and satellites], QC Physics, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], individual: TOI-561 (TIC 377064495, Gaia DR2 3850421005290172416) [Star], astro-ph.EP, Humanities, Astrophysics - Earth and Planetary Astrophysics
Abstract

Based on HARPS-N radial velocities (RVs) and TESS photometry, we present a full characterisation of the planetary system orbiting the late G dwarf TOI-561. After the identification of three transiting candidates by TESS, we discovered two additional external planets from RV analysis. RVs cannot confirm the outer TESS transiting candidate, which would also make the system dynamically unstable. We demonstrate that the two transits initially associated with this candidate are instead due to single transits of the two planets discovered using RVs. The four planets orbiting TOI-561 include an ultra-short period (USP) super-Earth (TOI-561 b) with period $P_{\rm b} = 0.45$ d, mass $M_{\rm b} =1.59 \pm 0.36$ M$_\oplus$ and radius $R_{\rm b}=1.42 \pm 0.07$ R$_\oplus$, and three mini-Neptunes: TOI-561 c, with $P_{\rm c} = 10.78$ d, $M_{\rm c} = 5.40 \pm 0.98$ M$_\oplus$, $R_{\rm c}= 2.88 \pm 0.09$ R$_\oplus$; TOI-561 d, with $P_{\rm d} = 25.6$ d, $M_{\rm d} = 11.9 \pm 1.3$ M$_\oplus$, $R_{\rm d} = 2.53 \pm 0.13$ R$_\oplus$; and TOI-561 e, with $P_{\rm e} = 77.2$ d, $M_{\rm e} = 16.0 \pm 2.3$ M$_\oplus$, $R_{\rm e} = 2.67 \pm 0.11$ R$_\oplus$. Having a density of $3.0 \pm 0.8$ g cm$^{-3}$, TOI-561 b is the lowest density USP planet known to date. Our N-body simulations confirm the stability of the system and predict a strong, anti-correlated, long-term transit time variation signal between planets d and e. The unusual density of the inner super-Earth and the dynamical interactions between the outer planets make TOI-561 an interesting follow-up target., 20 pages, 12 figures. Accepted for publication in MNRAS

Published
2021

36. ESPRESSO high-resolution transmission spectroscopy of WASP-76 b

Author

S. Hojjatpanah, L. Genolet, Matteo Genoni, Paolo Molaro, Edoardo Maria Alberto Redaelli, T. Bandy, A. Segovia, Jorge Lillo-Box, Diogo Alves, A. Suárez Mascareño, Olivier Demangeon, Vincent Bourrier, João P. Faria, Julia V. Seidel, F. Tenegi, P. Figueira, Yann Alibert, Danuta Sosnowska, Giorgio Pariani, Matteo Aliverti, Antonino Bianco, M. Moschetti, J. Knudstrup, B. Delabre, M. Amate, Romain Allart, Olaf Iwert, Valentina D'Odorico, Francesco Borsa, Hugo M. Tabernero, J. L. Lizon, M. R. Zapatero Osorio, G. Avila, Paolo Conconi, Vardan Adibekyan, Alexandre Cabral, Ennio Poretti, Mário J. P. F. G. Monteiro, J. L. Rasilla, Andrea Mehner, Antonio Gouveia Oliveira, Filippo Maria Zerbi, Alessandro Sozzetti, François Bouchy, Luca Pasquini, Baptiste Lavie, Marco Landoni, E. Mueller, S. Deiries, Luca Oggioni, Nelson J. Nunes, R. Génova Santos, Claudio Cumani, João Coelho, S. C. C. Barros, Denis Mégevand, J. I. González Hernández, S. Santana-Tschudi, Paolo Santin, M. Affolter, Giuseppina Micela, Alessio Zanutta, G. Lo Curto, A. Fragoso, C. Allende Prieto, Pedro Santos, J. H. C. Martins, Antonio Manescau, Florian Kerber, Willy Benz, Hans Dekker, David Ehrenreich, Paolo Spanò, Rafael Rebolo, Xavier Dumusque, Cristina Martins, Núria Casasayas-Barris, Francesco Pepe, S. G. Sousa, Stefano Cristiani, C. Broeg, C. Maire, Andrea Modigliani, Stéphane Udry, Nuno C. Santos, Marco Riva, C. Lovis, Enric Palle, I. Hughes, P. Di Marcantonio, ITA, ESP, PRT, and CHE

Subjects
530 Physics, Continuum (design consultancy), FOS: Physical sciences, Astrophysics, 01 natural sciences, Molecular physics, Spectral line, Atmosphere, Espresso, Planet, 0103 physical sciences, Irradiation, 010303 astronomy & astrophysics, Spectrograph, Solar and Stellar Astrophysics (astro-ph.SR), Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, 520 Astronomy, Astronomy and Astrophysics, 500 Science, 620 Engineering, Transmission (telecommunications), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics - Earth and Planetary Astrophysics
Abstract

Aims. We report on ESPRESSO high-resolution transmission spectroscopic observations of two primary transits of the highly-irradiated, ultra-hot Jupiter-size planet WASP-76b. We investigate the presence of several key atomic and molecular features of interest that may reveal the atmospheric properties of the planet. Methods. We extracted two transmission spectra of WASP-76b with R approx 140,000 using a procedure that allowed us to process the full ESPRESSO wavelength range (3800-7880 A) simultaneously. We observed that at a high signal-to-noise ratio, the continuum of ESPRESSO spectra shows wiggles that are likely caused by an interference pattern outside the spectrograph. To search for the planetary features, we visually analysed the extracted transmission spectra and cross-correlated the observations against theoretical spectra of different atomic and molecular species. Results. The following atomic features are detected: Li I, Na I, Mg I, Ca II, Mn I, K I, and Fe I. All are detected with a confidence level between 9.2 sigma (Na I) and 2.8 sigma (Mg I). We did not detect the following species: Ti I, Cr I, Ni I, TiO, VO, and ZrO. We impose the following 1 sigma upper limits on their detectability: 60, 77, 122, 6, 8, and 8 ppm, respectively. Conclusions. We report the detection of Li I on WASP-76b for the first time. In addition, we found the presence of Na I and Fe I as previously reported in the literature. We show that the procedure employed in this work can detect features down to the level of ~ 0.1 % in the transmission spectrum and ~ 10 ppm by means of a cross-correlation method. We discuss the presence of neutral and singly ionised features in the atmosphere of WASP-76b., 20 pages, 19 figures, accepted for publication in Astronomy and Astrophysics

Published
2021
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37. TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley

Author

Gilbert A. Esquerdo, Walter Boschin, Lars A. Buchhave, Allyson Bieryla, Karen A. Collins, Eric L. N. Jensen, Nobuhiko Kusakabe, David F. Phillips, Chelsea X. Huang, Jack J. Lissauer, Steve B. Howell, Norio Narita, E. Girardin, Christopher A. Watson, Enric Palle, Damien Ségransan, R. D. Haywood, P. Guerra, David W. Latham, S. Giacalone, Jonathan Irwin, Avi Shporer, Keivan G. Stassun, Giampaolo Piotto, E. Esparza-Borges, Gloria Andreuzzi, Felipe Murgas, Marco Pedani, Francesco Pepe, Mercedes Lopez-Morales, Scott McDermott, Courtney D. Dressing, Robert Massey, Motohide Tamura, George R. Ricker, Annelies Mortier, Giuseppina Micela, Jessie L. Christiansen, Emilio Molinari, Pau Bosch-Cabot, Jon M. Jenkins, Roland Vanderspek, Aldo F. M. Fiorenzano, Samuel N. Quinn, Hannu Parviainen, Ken Rice, Avet Harutyunyan, Akihiko Fukui, Sara Seager, Elisa V. Quintana, Massimo Cecconi, Mark E. Rose, R. Cloutier, Luca Di Fabrizio, Joshua N. Winn, Alessandro Sozzetti, Arjun B. Savel, Andrew Collier Cameron, David Charbonneau, Rachel A. Matson, Michel Mayor, Dimitar Sasselov, Christophe Lovis, Stéphane Udry, Gábor Fűrész, Xavier Dumusque, Cloutier, R [0000-0001-5383-9393], Charbonneau, D [0000-0002-9003-484X], Stassun, KG [0000-0002-3481-9052], Murgas, F [0000-0001-9087-1245], Mortier, A [0000-0001-7254-4363], Massey, R [0000-0001-8879-7138], Lissauer, JJ [0000-0001-6513-1659], Latham, DW [0000-0001-9911-7388], Haywood, RD [0000-0001-9140-3574], Guerra, P [0000-0002-4308-2339], Giacalone, SA [0000-0002-8965-3969], Bieryla, A [0000-0001-6637-5401], Winn, J [0000-0002-4265-047X], Watson, CA [0000-0002-9718-3266], Vanderspek, R [0000-0001-6763-6562], Udry, S [0000-0001-7576-6236], Tamura, M [0000-0002-6510-0681], Sozzetti, A [0000-0002-7504-365X], Shporer, A [0000-0002-1836-3120], Ségransan, D [0000-0003-2355-8034], Seager, S [0000-0002-6892-6948], Savel, AB [0000-0002-2454-768X], Sasselov, D [0000-0001-7014-1771], Rose, M [0000-0003-4724-745X], Ricker, G [0000-0003-2058-6662], Rice, K [0000-0002-6379-9185], Quintana, EV [0000-0003-1309-2904], Quinn, SN [0000-0002-8964-8377], Piotto, G [0000-0002-9937-6387], Phillips, D [0000-0001-5132-1339], Pedani, M [0000-0002-5752-6260], Parviainen, H [0000-0001-5519-1391], Palle, E [0000-0003-0987-1593], Narita, N [0000-0001-8511-2981], Molinari, E [0000-0002-1742-7735], Micela, G [0000-0002-9900-4751], Mayor, M [0000-0002-9352-5935], Matson, RA [0000-0001-7233-7508], López-Morales, M [0000-0003-3204-8183], Kusakabe, N [0000-0001-9194-1268], Jensen, ELN [0000-0002-4625-7333], Jenkins, JM [0000-0002-4715-9460], Huang, CX [0000-0003-0918-7484], Howell, SB [0000-0002-2532-2853], Fukui, A [0000-0002-4909-5763], Esquerdo, GA [0000-0002-9789-5474], Esparza-Borges, E [0000-0002-2341-3233], Dumusque, X [0000-0002-9332-2011], Dressing, CD [0000-0001-8189-0233], Collins, KA [0000-0001-6588-9574], Cameron, AC [0000-0002-8863-7828], Christiansen, JL [0000-0002-8035-4778], Buchhave, LA [0000-0003-1605-5666], Boschin, W [0000-0001-9978-9109], Apollo - University of Cambridge Repository, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), Radial velocity, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Radius, 3rd-DAS, Sitting, Exoplantet strcuture, QC Physics, Space and Planetary Science, Planet, astro-ph.EP, Period (geology), QB Astronomy, Planetary system formation, Low mass stars, Astrophysics::Earth and Planetary Astrophysics, Transit photometry, QC, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics, QB
Abstract

Studies of close-in planets orbiting M dwarfs have suggested that the M dwarf radius valley may be well-explained by distinct formation timescales between enveloped terrestrials, and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally-driven mass loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short period planet TOI-1634 b ($P=0.989$ days, $F=121 F_{\oplus}$, $r_p = 1.790^{+0.080}_{-0.081} R_{\oplus}$) orbiting a nearby M2 dwarf ($K_s=8.7$, $R_s=0.45 R_{\odot}$, $M_s=0.50 M_{\odot}$) and whose size and orbital period sit within the M dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of $4.91^{+0.68}_{-0.70} M_{\oplus}$, which makes TOI-1634 b inconsistent with an Earth-like composition at $5.9\sigma$ and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky portion that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of the Earth favors the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with $M_s\lesssim 0.5 M_{\odot}$., Comment: 27 pages, 13 figures, accepted to AAS journals. Our time series are included as a csv file in the arXiv source files

Published
2021

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. Detection Limits of Low-mass, Long-period Exoplanets Using Gaussian Processes Applied to HARPS-N Solar Radial Velocities

Author

Christopher A. Watson, M. Lopez-Morales, Massimo Cecconi, L. Malavolta, R. D. Haywood, Timothy Milbourne, M. Gonzalez, Dimitar Sasselov, David F. Phillips, Xavier Dumusque, J. Maldonado, Ken Rice, H. M. Cegla, S. H. Saar, Stéphane Udry, Rosario Cosentino, D. W. Latham, N. Buchschacher, Elisa Molinari, Ronald L. Walsworth, Adriano Ghedina, Giuseppina Micela, Francesco Pepe, Alessandro Sozzetti, C. H. Li, Susan E. Thompson, D. Charbonneau, E. Poretti, Annelies Mortier, Nicholas Langellier, A. Collier Cameron, Marcello Lodi, Langellier, N [0000-0003-2107-3308], Milbourne, TW [0000-0001-5446-7712], Phillips, DF [0000-0001-5132-1339], Haywood, RD [0000-0001-9140-3574], Saar, SH [0000-0001-7032-8480], Mortier, A [0000-0001-7254-4363], Malavolta, L [0000-0002-6492-2085], Thompson, S [0000-0002-8039-194X], Cameron, AC [0000-0002-8863-7828], Dumusque, X [0000-0002-9332-2011], Cegla, HM [0000-0001-8934-7315], Latham, DW [0000-0001-9911-7388], Maldonado, J [0000-0002-2218-5689], Buchschacher, N [0000-0002-3697-1541], Cecconi, M [0000-0001-5701-2529], Charbonneau, D [0000-0002-9003-484X], Cosentino, R [0000-0003-1784-1431], Ghedina, A [0000-0003-4702-5152], Lodi, M [0000-0002-5432-9659], López-Morales, M [0000-0003-3204-8183], Micela, G [0000-0002-9900-4751], Molinari, E [0000-0002-1742-7735], Poretti, E [0000-0003-1200-0473], Rice, K [0000-0002-6379-9185], Sasselov, D [0000-0001-7014-1771], Sozzetti, A [0000-0002-7504-365X], Udry, S [0000-0001-7576-6236], Walsworth, RL [0000-0003-0311-4751], Apollo - University of Cambridge Repository, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
Radial velocity, astro-ph.SR, Solar activity, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 010309 optics, symbols.namesake, Long period, 0103 physical sciences, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, Gaussian regression, 010303 astronomy & astrophysics, Gaussian process, QC, Astrophysics::Galaxy Astrophysics, QB, Physics, Detection limit, Exoplanets, DAS, Astronomy and Astrophysics, Exoplanet, QC Physics, 13. Climate action, Space and Planetary Science, astro-ph.EP, symbols, Astrophysics::Earth and Planetary Astrophysics, Low Mass, astro-ph.IM
Abstract

Funding: A.C.C. acknowledges support from the Science and Technology Facilities Council (STFC) consolidated grant No. ST/R000824/1. Radial velocity (RV) searches for Earth-mass exoplanets in the habitable zone around Sun-like stars are limited by the effects of stellar variability on the host star. In particular, suppression of convective blueshift and brightness inhomogeneities due to photospheric faculae/plage and starspots are the dominant contribution to the variability of such stellar RVs. Gaussian process (GP) regression is a powerful tool for statistically modeling these quasi-periodic variations. We investigate the limits of this technique using 800 days of RVs from the solar telescope on the High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph. These data provide a well-sampled time series of stellar RV variations. Into this data set, we inject Keplerian signals with periods between 100 and 500 days and amplitudes between 0.6 and 2.4 m s−1. We use GP regression to fit the resulting RVs and determine the statistical significance of recovered periods and amplitudes. We then generate synthetic RVs with the same covariance properties as the solar data to determine a lower bound on the observational baseline necessary to detect low-mass planets in Venus-like orbits around a Sun-like star. Our simulations show that discovering planets with a larger mass (~0.5 m s−1) using current-generation spectrographs and GP regression will require more than 12 yr of densely sampled RV observations. Furthermore, even with a perfect model of stellar variability, discovering a true exo-Venus (~0.1 m s−1) with current instruments would take over 15 yr. Therefore, next-generation spectrographs and better models of stellar variability are required for detection of such planets. Postprint

Published
2021

40. Long-term stellar activity variations and their effect on radial-velocity measurements

Author

David F. Phillips, J. Costes, Annelies Mortier, Collier Cameron, Christopher A. Watson, S. H. Saar, Xavier Dumusque, Maximilian N. Günther, A. Thompson, James S. Jenkins, Ernst J. W. de Mooij, Mortier, Annelies [0000-0001-7254-4363], Apollo - University of Cambridge Repository, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
planets and satellites: detection, stars: chromospheres, FOS: Physical sciences, Convection, 01 natural sciences, solar-type [Stars], 010309 optics, 0103 physical sciences, techniques: radial velocities, stars: activity, media_common.cataloged_instance, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, European union, 010303 astronomy & astrophysics, QC, convection, Solar and Stellar Astrophysics (astro-ph.SR), media_common, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Horizon (archaeology), European research, Astronomy and Astrophysics, stars: solar-type, 3rd-DAS, Geodesy, radial velocities [Technique], Term (time), Radial velocity, detection [Planets and satellites], QC Physics, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, chromospheres [Stars], Astrophysics::Earth and Planetary Astrophysics, activity [Stars], Astrophysics - Earth and Planetary Astrophysics
Abstract

Long-term stellar activity variations can affect the detectability of long-period and Earth-analogue extrasolar planets. We have, for 54 stars, analysed the long-term trend of five activity indicators: log$R'_\mathrm{{HK}}$, the cross-correlation function (CCF) bisector span, CCF full-width-at-half-maximum, CCF contrast, and the area of the Gaussian fit to the CCF; and studied their correlation with the RVs. The sign of the correlations appears to vary as a function of stellar spectral type, and the transition in sign signals a noteworthy change in the stellar activity properties where earlier type stars appear more plage dominated. These transitions become more clearly defined when considered as a function of the convective zone depth. Therefore, it is the convective zone depth (which can be altered by stellar metallicity) that appears to be the underlying fundamental parameter driving the observed activity correlations. In addition, for most of the stars, we find that the RVs become increasingly red-shifted as activity levels increase, which can be explained by the increase in the suppression of convective blue-shift. However, we also find a minority of stars where the RVs become increasingly blue-shifted as activity levels increase. Finally, using the correlation found between activity indicators and RVs, we removed RV signals generated by long-term changes in stellar activity. We find that performing simple cleaning of such long-term signals enables improved planet detection at longer orbital periods., Comment: 22 pages, 9 figures, accepted for publication in the Monthly Notices of the Royal Astronomical Society

Published
2021

41. Estimating Magnetic Filling Factors from Simultaneous Spectroscopy and Photometry: Disentangling Spots, Plage, and Network

Author

Xavier Dumusque, Adriano Ghedina, Andrew Vanderburg, Christopher A. Watson, Ronald L. Walsworth, Heather M. Cegla, Marcello Lodi, Mercedes López-Morales, T. W. Milbourne, Alessandro Sozzetti, M. Cecconi, Raphaëlle D. Haywood, Rosario Cosentino, Annelies Mortier, Nicholas Langellier, A. Collier Cameron, M. Gonzalez, Luca Malavolta, S. H. Saar, David W. Latham, Samantha Thompson, Jesus Maldonado, Lars A. Buchhave, David F. Phillips, 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
Radial velocity, Brightness, Solar activity, FOS: Physical sciences, Astrophysics, 01 natural sciences, 010309 optics, Photometry (optics), symbols.namesake, Observatory, 0103 physical sciences, Exoplanet detection methods, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, MCC, Physics, Filling factor, Exoplanets, Astronomy and Astrophysics, 3rd-DAS, Exoplanet, Solar telescope, Solar active regions, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, symbols, Astrophysics::Earth and Planetary Astrophysics, Doppler effect
Abstract

State of the art radial velocity (RV) exoplanet searches are limited by the effects of stellar magnetic activity. Magnetically active spots, plage, and network regions each have different impacts on the observed spectral lines, and therefore on the apparent stellar RV. Differentiating the relative coverage, or filling factors, of these active regions is thus necessary to differentiate between activity-driven RV signatures and Doppler shifts due to planetary orbits. In this work, we develop a technique to estimate feature-specific magnetic filling factors on stellar targets using only spectroscopic and photometric observations. We demonstrate linear and neural network implementations of our technique using observations from the solar telescope at HARPS-N, the HK Project at the Mt. Wilson Observatory, and the Total Irradiance Monitor onboard SORCE. We then compare the results of each technique to direct observations by the Solar Dynamics Observatory (SDO). Both implementations yield filling factor estimates that are highly correlated with the observed values. Modeling the solar RVs using these filling factors reproduces the expected contributions of the suppression of convective blueshift and rotational imbalance due to brightness inhomogeneities. Both implementations of this technique reduce the overall activity-driven RMS RVs from 1.64 m/s to 1.02 m/s, corresponding to a 1.28 m/s reduction in the RMS variation. The technique provides an additional 0.41 m/s reduction in the RMS variation compared to traditional activity indicators., 16 pages, 6 figures, accepted by The Astrophysical Journal

Published
2021

42. ESPRESSO at VLT. On-sky performance and first results

Author

G. Avila, Alexandre Cabral, Andrea Mehner, S. Deiries, C. Allende Prieto, Vardan Adibekyan, Roberto Cirami, Manuel Abreu, Luca Pasquini, M. Affolter, Luca Oggioni, Igor Coretti, Nelson J. Nunes, J. Knudstrup, G. Lo Curto, Nuno C. Santos, C. Lovis, Enric Palle, Damien Ségransan, Filippo Maria Zerbi, Yann Alibert, Jose Luis Rasilla, I. Hughes, A. Fragoso, S. Santana Tschudi, T. M. Schmidt, Romain Allart, Florian Kerber, Antonino Bianco, R. Génova Santos, Mahmoudreza Oshagh, Matteo Genoni, A. Segovia, João P. Faria, Rafael Rebolo, Vincent Bourrier, M. Moschetti, Olivier Demangeon, M. A. Monteiro, Marco Landoni, Danuta Sosnowska, Valentina D'Odorico, Willy Benz, P. Figueira, François Bouchy, Baptiste Lavie, Andrea Modigliani, Marco Riva, L. Genolet, Matteo Aliverti, Paolo Santin, B. Delabre, Paolo Molaro, J. L. Lizon, F. Tenegi, M. R. Zapatero Osorio, Antonio Gouveia Oliveira, Francesco Pepe, Paolo Conconi, Stéphane Udry, Guido Cupani, Hugo M. Tabernero, S. G. Sousa, José Manuel Rebordão, Hans Dekker, T. Bandy, Ennio Poretti, S. C. C. Barros, D. Álvarez, A. Suárez Mascareño, Stefano Cristiani, C. Maire, J. I. González Hernández, Giuseppina Micela, Giorgio Calderone, V. Baldini, Xavier Dumusque, Alessandro Sozzetti, Claudio Cumani, João Coelho, M. Amate, Francesco Borsa, Olaf Iwert, Denis Mégevand, Cristina Martins, Antonio Manescau, Alessio Zanutta, Michael T. Murphy, C. Broeg, Mario Damasso, M. Mayor, Jorge Lillo-Box, Pedro Santos, P. Di Marcantonio, P. Spano, Edoardo Maria Alberto Redaelli, Diogo Alves, Giorgio Pariani, Mário J. P. F. G. Monteiro, David Ehrenreich, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Swiss National Science Foundation (SNSF), Fundacao para a Ciencia e a Tecnologia (FCT), European Research Council (ERC), Agencia Estatal de Investigación (AEI), and Australian Research Council

Subjects
Accuracy and precision, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, 7. Clean energy, law.invention, 010309 optics, Telescope, Espresso, Observatory, law, 0103 physical sciences, miscellaneous [Cosmology], spectrographs [Instrumentation], 010303 astronomy & astrophysics, Spectrograph, Instrumentation and Methods for Astrophysics (astro-ph.IM), Physics, Earth and Planetary Astrophysics (astro-ph.EP), Very Large Telescope, radial velocities [Techniques], Asteroseismology, Astronomy, Astronomy and Astrophysics, Exoplanet, detection [Planets and satellites], Space and Planetary Science, atmospheres [Planets and satellites], Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

ESPRESSO is the new high-resolution spectrograph of ESO's Very-Large Telescope (VLT). It was designed for ultra-high radial-velocity precision and extreme spectral fidelity with the aim of performing exoplanet research and fundamental astrophysical experiments with unprecedented precision and accuracy. It is able to observe with any of the four Unit Telescopes (UT) of the VLT at a spectral resolving power of 140,000 or 190,000 over the 378.2 to 788.7 nm wavelength range, or with all UTs together, turning the VLT into a 16-m diameter equivalent telescope in terms of collecting area, while still providing a resolving power of 70,000. We provide a general description of the ESPRESSO instrument, report on the actual on-sky performance, and present our Guaranteed-Time Observation (GTO) program with its first results. ESPRESSO was installed on the Paranal Observatory in fall 2017. Commissioning (on-sky testing) was conducted between December 2017 and September 2018. The instrument saw its official start of operations on October 1st, 2018, but improvements to the instrument and re-commissioning runs were conducted until July 2019. The measured overall optical throughput of ESPRESSO at 550 nm and a seeing of 0.65 arcsec exceeds the 10% mark under nominal astro-climatic conditions. We demonstrate a radial-velocity precision of better than 25 cm/s during one night and 50 cm/s over several months. These values being limited by photon noise and stellar jitter show that the performanceis compatible with an instrumental precision of 10 cm/s. No difference has been measured across the UTs neither in throughput nor RV precision. The combination of the large collecting telescope area with the efficiency and the exquisite spectral fidelity of ESPRESSO opens a new parameter space in RV measurements, the study of planetary atmospheres, fundamental constants, stellar characterisation and many other fields., 26 pages, 28 figures

Published
2021

43. Wolf 503 b: Characterization of a Sub-Neptune Orbiting a Metal-Poor K Dwarf

Author

Lauren M. Weiss, Ian J. M. Crossfield, Sean M. Mills, Mercedes Lopez-Morales, Björn Benneke, Johanna Teske, Varoujan Gorjian, Howard Isaacson, Sharon X. Wang, Emilio Molinari, Samuel K. Grunblatt, R. Paul Butler, Jennifer Burt, Ashley Chontos, Grzegorz Nowak, Aida Behmard, Stephen A. Shectman, Erik A. Petigura, Avet Harutyunyan, Annelies Mortier, Ennio Poretti, Xavier Dumusque, Michel Mayor, Andrew W. Howard, Molly R. Kosiarek, Evangelos Nagel, Rafael Luque, Jeffrey D. Crane, Enric Palle, David W. Latham, Adriano Ghedina, Aldo S. Bonomo, Benjamin J. Fulton, Rosario Cosentino, Sarah Blunt, Aldo F. M. Fiorenzano, Alessandro Sozzetti, Alex S. Polanski, Polanski, AS [0000-0001-7047-8681], Burt, JA [0000-0002-0040-6815], Nowak, G [0000-0002-7031-7754], López-Morales, M [0000-0003-3204-8183], Mortier, A [0000-0001-7254-4363], Poretti, E [0000-0003-1200-0473], Behmard, A [0000-0003-0012-9093], Benneke, B [0000-0001-5578-1498], Blunt, S [0000-0002-3199-2888], Bonomo, AS [0000-0002-6177-198X], Butler, RP [0000-0003-1305-3761], Chontos, A [0000-0003-1125-2564], Crane, JD [0000-0002-5226-787X], Dumusque, X [0000-0002-9332-2011], Fulton, BJ [0000-0003-3504-5316], Ghedina, A [0000-0003-4702-5152], Grunblatt, SK [0000-0003-4976-9980], Howard, AW [0000-0001-8638-0320], Isaacson, H [0000-0002-0531-1073], Kosiarek, MR [0000-0002-6115-4359], Latham, DW [0000-0001-9911-7388], Luque, R [0000-0002-4671-2957], Mayor, M [0000-0002-9352-5935], Mills, SM [0000-0002-4535-6241], Molinari, E [0000-0002-1742-7735], Nagel, E [0000-0002-4019-3631], Pallé, E [0000-0003-0987-1593], Petigura, EA [0000-0003-0967-2893], Shectman, SA [0000-0002-8681-6136], Sozzetti, A [0000-0002-7504-365X], Wang, SX [0000-0002-6937-9034], Weiss, LM [0000-0002-3725-3058], and Apollo - University of Cambridge Repository

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, Characterization (mathematics), 01 natural sciences, 010309 optics, Transmission spectroscopy, Radial velocity, Photometry (optics), Space and Planetary Science, Neptune, 0103 physical sciences, astro-ph.EP, Eccentricity (mathematics), 010303 astronomy & astrophysics, Mass fraction, Astrophysics - Earth and Planetary Astrophysics
Abstract

Using radial velocity measurements from four instruments, we report the mass and density of a $2.043\pm0.069 ~\rm{R}_{\oplus}$ sub-Neptune orbiting the quiet K-dwarf Wolf 503 (HIP 67285). In addition, we present improved orbital and transit parameters by analyzing previously unused short-cadence $K2$ campaign 17 photometry and conduct a joint radial velocity-transit fit to constrain the eccentricity at $0.41\pm0.05$. The addition of a transit observation by $Spitzer$ also allows us to refine the orbital ephemeris in anticipation of further follow-up. Our mass determination, $6.26^{+0.69}_{-0.70}~\rm{M}_{\odot}$, in combination with the updated radius measurements, gives Wolf 503 b a bulk density of $\rho = 2.92\pm ^{+0.50}_{-0.44}$ $\rm{g}~\rm{cm}^{-3}$. Using interior composition models, we find this density is consistent with an Earth-like core with either a substantial $\rm{H}_2\rm{O}$ mass fraction ($45^{+19.12}_{-16.15}\%$) or a modest H/He envelope ($0.5\pm0.28\%$). The low H/He mass fraction, along with the old age of Wolf 503 ($11\pm2$ Gyrs), makes this sub-Neptune an opportune subject for testing theories of XUV-driven mass loss while the brightness of its host ($J=8.3$ mag) makes it an attractive target for transmission spectroscopy., Comment: Accepted to ApJ 2021 July 15

Published
2021
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44. Separating planetary reflex Doppler shifts from stellar variability in the wavelength domain

Author

Alessandro Sozzetti, Emilio Molinari, Annelies Mortier, A. Collier Cameron, Suzanne Aigrain, Adriano Ghedina, Xavier Dumusque, Eric B. Ford, Giampaolo Piotto, Raphaëlle D. Haywood, Ennio Poretti, M. Gonzalez, Rosario Cosentino, H. M. Cegla, Francesco Pepe, Christopher A. Watson, David W. Latham, Samantha Thompson, Didier Queloz, Marcello Lodi, Mercedes López-Morales, David F. Phillips, Giuseppina Micela, J. San Juan, Massimo Cecconi, Lars A. Buchhave, A Szentgyorgyi, M. Cretignier, Damien Ségransan, Stéphane Udry, Sahar Shahaf, Science & Technology Facilities Council, University of St Andrews. St Andrews Centre for Exoplanet Science, University of St Andrews. School of Physics and Astronomy, Mortier, Annelies [0000-0001-7254-4363], Queloz, Didier [0000-0002-3012-0316], and Apollo - University of Cambridge Repository

Subjects
statistical [Methods], photosphere [Sun], FOS: Physical sciences, 01 natural sciences, Domain (software engineering), spectroscopic [Techniques], Methods statistical, 010104 statistics & probability, symbols.namesake, Software, techniques: radial velocities, 0103 physical sciences, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, 0101 mathematics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, methods: statistical, Photosphere, radial velocities [Techniques], business.industry, Sun: photosphere, Astronomy, planets and satellites: general, Astronomy and Astrophysics, DAS, general [Planets and satellites], Wavelength, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, symbols, Reflex, general. [Planets and satellites], Astrophysics::Earth and Planetary Astrophysics, business, Astrophysics - Instrumentation and Methods for Astrophysics, Doppler effect, techniques: spectroscopic, Astrophysics - Earth and Planetary Astrophysics
Abstract

Stellar magnetic activity produces time-varying distortions in the photospheric line profiles of solar-type stars. These lead to systematic errors in high-precision radial-velocity measurements, which limit efforts to discover and measure the masses of low-mass exoplanets with orbital periods of more than a few tens of days. We present a new data-driven method for separating Doppler shifts of dynamical origin from apparent velocity variations arising from variability-induced changes in the stellar spectrum. We show that the autocorrelation function (ACF) of the cross-correlation function used to measure radial velocities is effectively invariant to translation. By projecting the radial velocities on to a subspace labelled by the observation identifiers and spanned by the amplitude coefficients of the ACF's principal components, we can isolate and subtract velocity perturbations caused by stellar magnetic activity. We test the method on a 5-year time sequence of 853 daily 15-minute observations of the solar spectrum from the HARPS-N instrument and solar-telescope feed on the 3.58-m Telescopio Nazionale Galileo. After removal of the activity signals, the heliocentric solar velocity residuals are found to be Gaussian and nearly uncorrelated. We inject synthetic low-mass planet signals with amplitude $K=40$ cm s$^{-1}$ into the solar observations at a wide range of orbital periods. Projection into the orthogonal complement of the ACF subspace isolates these signals effectively from solar activity signals. Their semi-amplitudes are recovered with a precision of $\sim~6.6$ cm s$^{-1}$, opening the door to Doppler detection and characterization of terrestrial-mass planets around well-observed, bright main-sequence stars across a wide range of orbital periods., 19 pages, 15 figures, accepted 2 May 2021 for publication in MNRAS

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. Mass determinations of the three mini-Neptunes transiting TOI-125

Author

Farzana Meru, Matías R. Díaz, John H. Livingston, Florian Rodler, Samuel N. Quinn, Pablo Rojas, Heike Rauer, Diana Kossakowski, Isabelle Boisse, George R. Ricker, P. T. Boyd, Ravit Helled, Judith Korth, S. C. C. Barros, L. A. dos Santos, A. P. Hatzes, S. Sabotta, Rafael Luque, M. Stalport, Andrew Vanderburg, Jason H. Steffen, Vincent Van Eylen, Edward M. Bryant, Jon M. Jenkins, David J. Armstrong, L. González-Cuesta, S. Hojjatpanah, Norio Narita, Felipe Murgas, Savita Mathur, J. F. Otegi, Paul Wilson, Iskra Georgieva, Nicolás T. Kurtovic, Sara Seager, Emeline Bolmont, Xavier Dumusque, Jose I. Vines, M. Esposito, Z. M. Berdinas, Sascha Grziwa, Olivier Demangeon, J. M. Almenara, O. Mousis, Julia V. Seidel, D. J. A. Brown, T. Lopez, A. Santerne, S. G. Sousa, Benjamin F. Cooke, Davide Gandolfi, R. A. Garcia, Eric B. Ting, Fei Dai, David W. Latham, Daniel Bayliss, Romain Allart, Peter J. Wheatley, François Bouchy, Christopher J. Burke, Vardan Adibekyan, Seth Redfield, Hugh P. Osborn, Natalia Guerrero, Joshua N. Winn, Malcolm Fridlund, Martin Turbet, Louise D. Nielsen, Chris Henze, Caroline Dorn, J. Dittman, K. W. F. Lam, Carina M. Persson, William D. Cochran, Jorge Lillo-Box, Rodrigo F. Díaz, Stéphane Udry, Nuno C. Santos, David Barrado, Enric Palle, James S. Jenkins, Roland Vanderspek, 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), Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Vanderburg, A. [0000-0001-7246-5438], Dos Santos, L. [0000-0002-2248-3838], Barrado, D. [0000-0002-5971-9242], Cochran, W. [0000-0001-9662-3496], Lillo Box, J. [0000-0003-3742-1987], Barros, S. [0000-0003-2434-3625], Stalport, M. [0000-0003-0996-6402], Dorn, C. [0000-0001-6110-4610], Nielsen, L. D. [0000-0002-5254-2499], Seidel, J. V. [0000-0002-7990-9596], Diaz, M. R. [0000-0002-2100-3257], Bolmont, E. [0000-0001-5657-4503], Adibekyan, V. [0000-0002-0601-6199], Van Eylen, V. [0000-0001-5542-8870], Armstrong, D. [0000-0002-5080-4117], Korth, J. [0000-0002-0076-6239], Díaz, R. [0000-0001-9289-5160], Santos, N. [0000-0003-4422-2919], Luque, R. [0000-0002-4671-2957], Turbet, M. [0000-0003-2260-9856], Mathur, S. [0000-0002-0129-0316], Strom, P. A. [0000-0002-7823-1090], Sabotta, S. [0000-0001-9078-5574], Wheatley, P. [0000-0003-1452-2240], Hojjatpanah, S. [0000-0002-0417-1902], Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT), Swiss National Science Foundation (SNSF), Deutsche Forschungsgemeinschaft (DFG), Agencia Estatal de Investigación (AEI), European Southern Observatory (ESO), Swiss National Centre of Competence inResearch (NCCR), National Aeronautics and Space Administration (NASA), Fundacao para a Ciencia e a Tecnologia (FCT), European Research Council (ERC), European Southern Observatory, STFC via an Ernest Rutherford Fellowship, FEDER -Fundo Europeu de Desenvolvimento Regional through COMPETE2020-Programa Operacional Competitividade e Internacionalizacao, Portuguese Foundation for Science and Technology, CONICYT-PFCHA/Doctorado Nacional, Comision Nacional de Investigacion Cientifica y Tecnologica CONICYT FONDECYT, German Research Foundation (DFG), Spanish State Research Agency (AEI), Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, and Spanish Ministry under the Ramon y Cajal fellowship

Subjects
010504 meteorology & atmospheric sciences, Planets and satellites: detection, Planets and satellites: individual: (TOI-125, TIC 52368076), FOS: Physical sciences, 01 natural sciences, Neptune, Planet, TIC 52368076), 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], individual: TOI-125, TIC 52368076 [Planets and satellites], Ecliptic, Astronomy, Astronomy and Astrophysics, Radius, Planets and satellites: detection, Orbital period, Exoplanet, Radial velocity, detection [Planets and satellites], Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics - Earth and Planetary Astrophysics, Planets and satellites: individual: (TOI-125
Abstract

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

Published
2020

47. Testing the Spectroscopic Extraction of Suppression of Convective Blueshift

Author

Christopher A. Watson, S. H. Saar, M. Miklos, N. Meunier, Raphaëlle D. Haywood, Annelies Mortier, Ennio Poretti, Nicholas Langellier, Ronald L. Walsworth, Alessandro Sozzetti, Samantha Thompson, M. Cecconi, Chih-Hao Li, Heather M. Cegla, Jesus Maldonado, David F. Phillips, Mercedes López-Morales, Luca Malavolta, Rosario Cosentino, Xavier Dumusque, Adriano Ghedina, T. W. Milbourne, Emilio Molinari, and Dimitar Sasselov

Subjects
Solar minimum, Radial velocity, Solar faculae, 010504 meteorology & atmospheric sciences, Plages, Solar activity, FOS: Physical sciences, Astrophysics, Solar granulation, Sunspots, Exoplanet detection methods, 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Photosphere, Stellar atmosphere, Astronomy and Astrophysics, Exoplanet, Blueshift, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Efforts to detect low-mass exoplanets using stellar radial velocities (RVs) are currently limited by magnetic photospheric activity. Suppression of convective blueshift is the dominant magnetic contribution to RV variability in low-activity Sun-like stars. Due to convective plasma motions, the magnitude of RV contributions from the suppression of convective blueshift is related to the depth of formation of photospheric spectral lines of a given species used to compute the RV time series. Meunier et al. (2017), used this relation to demonstrate a method for spectroscopic extraction of the suppression of convective blueshift in order to isolate RV contributions, including planetary RVs, that contribute equally to the timeseries for each spectral line. Here, we extract disk-integrated solar RVs from observations over a 2.5 year time span made with the solar telescope integrated with the HARPS-N spectrograph at the Telescopio Nazionale Galileo (La Palma, Canary Islands, Spain). We apply the methods outlined by Meunier et al. (2017). We are not, however, able to isolate physically meaningful contributions of the suppression of convective blueshift from this solar dataset, potentially because our dataset is from solar minimum when the suppression of convective blueshift may not sufficiently dominate activity contributions to RVs. This result indicates that, for low-activity Sun-like stars, one must include additional RV contributions from activity sources not considered in the Meunier et al. (2017) model at different timescales as well as instrumental variation in order to reach the sub-meter per second RV sensitivity necessary to detect low-mass planets in orbit around Sun-like stars., 8 pages, 4 figures, 4 tables, Published by ApJ (1/15/2020)

Published
2020

48. Identifying Exoplanets with Deep Learning. IV. Removing Stellar Activity Signals from Radial Velocity Measurements Using Neural Networks

Author

Zoe. L. de Beurs, Andrew Vanderburg, Christopher J. Shallue, Xavier Dumusque, Andrew Collier Cameron, Christopher Leet, Lars A. Buchhave, Rosario Cosentino, Adriano Ghedina, Raphaëlle D. Haywood, Nicholas Langellier, David W. Latham, Mercedes López-Morales, Michel Mayor, Giusi Micela, Timothy W. Milbourne, Annelies Mortier, Emilio Molinari, Francesco Pepe, David F. Phillips, Matteo Pinamonti, Giampaolo Piotto, Ken Rice, Dimitar Sasselov, Alessandro Sozzetti, Stéphane Udry, Christopher A. Watson, De Beurs, ZL [0000-0002-7564-6047], Vanderburg, A [0000-0001-7246-5438], Shallue, CJ [0000-0002-7585-9974], Dumusque, X [0000-0002-9332-2011], Cameron, AC [0000-0002-8863-7828], Leet, C [0000-0003-2369-0481], Buchhave, LA [0000-0003-1605-5666], Cosentino, R [0000-0003-1784-1431], Ghedina, A [0000-0003-4702-5152], Haywood, RD [0000-0001-9140-3574], Langellier, N [0000-0003-2107-3308], Latham, DW [0000-0001-9911-7388], López-Morales, M [0000-0003-3204-8183], Mayor, M [0000-0002-9352-5935], Micela, G [0000-0002-9900-4751], Milbourne, TW [0000-0001-5446-7712], Mortier, A [0000-0001-7254-4363], Molinari, E [0000-0002-1742-7735], Phillips, DF [0000-0001-5132-1339], Pinamonti, M [0000-0002-4445-1845], Piotto, G [0000-0002-9937-6387], Rice, K [0000-0002-6379-9185], Sasselov, D [0000-0001-7014-1771], Sozzetti, A [0000-0002-7504-365X], Udry, S [0000-0001-7576-6236], Apollo - University of Cambridge Repository, Apollo-University Of Cambridge Repository, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
QA75, FOS: Computer and information sciences, Radial velocity, Computer Science - Machine Learning, astro-ph.SR, Exoplanet astronomy, QA75 Electronic computers. Computer science, cs.LG, FOS: Physical sciences, Machine Learning (cs.LG), QB Astronomy, Instrumentation and Methods for Astrophysics (astro-ph.IM), QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, Earth and Planetary Astrophysics (astro-ph.EP), The Solar System, Exoplanets, and Astrobiology, Astronomy and Astrophysics, DAS, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, astro-ph.EP, Convolutional neural networks, Astrophysics - Instrumentation and Methods for Astrophysics, astro-ph.IM, Astrophysics - Earth and Planetary Astrophysics
Abstract

Exoplanet detection with precise radial velocity (RV) observations is currently limited by spurious RV signals introduced by stellar activity. We show that machine learning techniques such as linear regression and neural networks can effectively remove the activity signals (due to starspots/faculae) from RV observations. Previous efforts focused on carefully filtering out activity signals in time using modeling techniques like Gaussian Process regression (e.g. Haywood et al. 2014). Instead, we systematically remove activity signals using only changes to the average shape of spectral lines, and no information about when the observations were collected. We trained our machine learning models on both simulated data (generated with the SOAP 2.0 software; Dumusque et al. 2014) and observations of the Sun from the HARPS-N Solar Telescope (Dumusque et al. 2015; Phillips et al. 2016; Collier Cameron et al. 2019). We find that these techniques can predict and remove stellar activity from both simulated data (improving RV scatter from 82 cm/s to 3 cm/s) and from more than 600 real observations taken nearly daily over three years with the HARPS-N Solar Telescope (improving the RV scatter from 1.753 m/s to 1.039 m/s, a factor of ~ 1.7 improvement). In the future, these or similar techniques could remove activity signals from observations of stars outside our solar system and eventually help detect habitable-zone Earth-mass exoplanets around Sun-like stars., Comment: 28 pages, 14 figures, Accepted for publication in the Astronomical Journal

Published
2020
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49. Erratum: 'An 11 Earth-mass, Long-period Sub-Neptune Orbiting a Sun-like Star' (2019, AJ, 158, 165)

Author

Andrew Collier Cameron, Ken Rice, Emilio Molinari, Rosario Cosentino, Alessandro Sozzetti, A. F. Martinez Fiorenzano, Stéphane Udry, Raphaëlle D. Haywood, Ennio Poretti, David F. Phillips, Suzanne Aigrain, Courtney D. Dressing, Annelies Mortier, Aldo S. Bonomo, Mercedes López-Morales, A. Coffinet, Charles D. Fortenbach, Xavier Dumusque, Giampaolo Piotto, Mario Damasso, David Charbonneau, Luca Malavolta, Li Zeng, David W. Latham, Vinesh M. Rajpaul, Andrew W. Mayo, Giuseppina Micela, Francesco Pepe, Lars A. Buchhave, and Logan A. Pearce

Subjects
Insolation, Physics, 010504 meteorology & atmospheric sciences, Flux, Astronomy and Astrophysics, Astrophysics, Star (graph theory), Astronomy & Astrophysics, Earth mass, Table (information), 01 natural sciences, Space and Planetary Science, Neptune, Planet, Long period, Physics::Space Physics, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, Astronomical and Space Sciences, 0105 earth and related environmental sciences
Abstract

Author(s): Mayo, AW; Rajpaul, VM; Buchhave, LA; Dressing, CD; Mortier, A; Zeng, L; Fortenbach, CD; Aigrain, S; Bonomo, AS; Cameron, AC; Charbonneau, D; Coffinet, A; Cosentino, R; Damasso, M; Dumusque, X; Fiorenzano, AFM; Haywood, RD; Latham, DW; Lopez-Morales, M; Malavolta, L; Micela, G; Molinari, E; Pearce, L; Pepe, F; Phillips, D; Piotto, G; Poretti, E; Rice, K; Sozzetti, A; Udry, S | Abstract: The semimajor axis and planet insolation flux of Kepler-538b were incorrectly calculated in the published article. This error did not impact any other parameters or any other results in the paper. Table 2 has been included in full here with the corrected semimajor axis and planet insolation flux values. We thank Arbab I. Arbab and Charles D. Fortenbach for bringing this to our attention.(Table Presented).

Published
2020

50. The spectral impact of magnetic activity on disc-integrated HARPS-N solar observations: exploring new activity indicators

Author

Giuseppina Micela, S. H. Saar, Ronald L. Walsworth, Rosario Cosentino, Annelies Mortier, David F. Phillips, A. Collier Cameron, Xavier Dumusque, Suzanne Aigrain, David W. Latham, Samantha Thompson, E. J. W. de Mooij, Raphaëlle D. Haywood, Ennio Poretti, T. W. Milbourne, Alessandro Sozzetti, M. López-Morales, Heather M. Cegla, Adriano Ghedina, David Charbonneau, A. Thompson, Emilio Molinari, J. Costes, Christopher A. Watson, 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, NDAS, FOS: Physical sciences, faculae [Sun], Sun: faculae, plages, plages, 01 natural sciences, 010309 optics, Sun: activity, techniques: radial velocities, 0103 physical sciences, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, activity [Sun], faculae, plages [Sun], Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, radial velocities [Techniques], Astronomy, Astronomy and Astrophysics, detection [Planets and satellites], QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Stellar activity is the major roadblock on the path to finding true Earth-analogue planets with the Doppler technique. Thus, identifying new indicators that better trace magnetic activity (i.e. faculae and spots) is crucial to aid in disentangling these signals from that of a planet's Doppler wobble. In this work, we investigate activity related features as seen in disk-integrated spectra from the HARPS-N solar telescope. We divide high-activity spectral echelle orders by low-activity master templates (as defined using both log R'HK and images from the Solar Dynamics Observatory, SDO), creating "relative spectra". With resolved images of the surface of the Sun (via SDO), the faculae and spot filling factors can be calculated, giving a measure of activity independent of, and in addition to, log R'HK. We find pseudo-emission (and pseudo-absorption) features in the relative spectra that are similar to those reported in our previous work on alpha Cen B. In alpha Cen B, the features are shown to correlate better to changes in faculae filling factor than spot filling factor. In this work we more confidently identify changes in faculae coverage of the visible hemisphere of the Sun as the source of features produced in the relative spectra. Finally, we produce trailed spectra to observe the RV component of the features, which show that the features move in a redward direction as one would expect when tracking active regions rotating on the surface of a star., Comment: 13 pages, 10 figures, accepted for publication in the Monthly Notices of the Royal Astronomical Society

Published
2020
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