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113 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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10. 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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11. 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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13. 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. 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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16. 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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17. 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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18. 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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19. 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

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

29. 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

30. 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

31. 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

32. 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

33. 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

34. 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

35. 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

36. Transits of Known Planets Orbiting a Naked-eye Star

Author

Stephen R. Kane, Tiago L. Campante, Ekrem Murat Esmer, Rodrigo F. Díaz, Özgür Baştürk, Magali Deleuil, Stéphane Udry, Natalie R. Hinkel, Howard Isaacson, Simon J. O'Toole, Brad D. Carter, Maxime Marmier, Damien Ségransan, Margaret C. Turnbull, R. Paul Butler, H. P. Osborn, Jason T. Wright, Francesco Pepe, Christophe Lovis, Andrew W. Howard, Xavier Dumusque, Jon M. Jenkins, François Bouchy, Sara Seager, Jeremy Bailey, Robert A. Wittenmyer, Andrew Vanderburg, Geoffrey W. Marcy, Joshua N. Winn, Duncan J. Wright, Roland Vanderspek, Martti H. Kristiansen, Louise D. Nielsen, Darin Ragozzine, Hugh R. A. Jones, Jacob L. Bean, David Ehrenreich, Tansu Daylan, Selçuk Yalçınkaya, George R. Ricker, C. G. Tinney, Romain Allart, David W. Latham, Jonathan Horner, Colby Ostberg, Tara Fetherolf, Paul A. Dalba, Teo Mocnik, Laboratoire d'Astrophysique de Marseille (LAM), and 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)

Subjects
Radial velocity, 010504 meteorology & atmospheric sciences, Star (game theory), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Exoplanets, Astronomy and Astrophysics, Planetary system, Exoplanet, Exoplanet structure, Orbit, Stars, Photometry (astronomy), 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics, Transit photometry, Exoplanet atmospheres, Astrophysics - Earth and Planetary Astrophysics
Abstract

Some of the most scientifically valuable transiting planets are those that were already known from radial velocity (RV) surveys. This is primarily because their orbits are well characterized and they preferentially orbit bright stars that are the targets of RV surveys. The Transiting Exoplanet Survey Satellite ({\it TESS}) provides an opportunity to survey most of the known exoplanet systems in a systematic fashion to detect possible transits of their planets. HD~136352 (Nu$^2$~Lupi) is a naked-eye ($V = 5.78$) G-type main-sequence star that was discovered to host three planets with orbital periods of 11.6, 27.6, and 108.1 days via RV monitoring with the HARPS spectrograph. We present the detection and characterization of transits for the two inner planets of the HD~136352 system, revealing radii of $1.482^{+0.058}_{-0.056}$~$R_\oplus$ and $2.608^{+0.078}_{-0.077}$~$R_\oplus$ for planets b and c, respectively. We combine new HARPS observations with RV data from Keck/HIRES and the AAT, along with {\it TESS} photometry from Sector 12, to perform a complete analysis of the system parameters. The combined data analysis results in extracted bulk density values of $\rho_b = 7.8^{+1.2}_{-1.1}$~gcm$^{-3}$ and $\rho_c = 3.50^{+0.41}_{-0.36}$~gcm$^{-3}$ for planets b and c, respectively, thus placing them on either side of the radius valley. The combination of the multi-transiting planet system, the bright host star, and the diversity of planetary interiors and atmospheres means this will likely become a cornerstone system for atmospheric and orbital characterization of small worlds., Comment: 13 pages, 4 figures, 3 tables, accepted for publication in the Astronomical Journal

Published
2020

37. Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS). III. Atmospheric structure of the misaligned ultra-hot Jupiter WASP-121b

Author

C. Melo, Francesco Pepe, A. Suarez-Mascareno, Nicola Astudillo-Defru, M. Cretignier, Damien Ségransan, T. Kuntzer, Valerio Nascimbeni, Monika Lendl, Aurélien Wyttenbach, C. Lovis, Kevin Heng, Heather M. Cegla, H. Giles, Stéphane Udry, Romain Allart, Lorenzo Pino, H. J. Hoeijmakers, Felipe Murgas, Xavier Dumusque, Baptiste Lavie, David Ehrenreich, Daniel Kitzmann, and Vincent Bourrier

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Planetary system, 01 natural sciences, Exoplanet, Tidal locking, Jupiter, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Hot Jupiter, Differential rotation, Transit (astronomy), Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

Ultra-hot Jupiters offer interesting prospects for expanding our theories on dynamical evolution and the properties of extremely irradiated atmospheres. In this context, we present the analysis of new optical spectroscopy for the transiting ultra-hot Jupiter WASP-121b. We first refine the orbital properties of WASP-121b, which is on a nearly polar (obliquity $\psi^{\rm North}$=88.1$\pm$0.25$^{\circ}$ or $\psi^{\rm South}$=91.11$\pm$0.20$^{\circ}$) orbit, and exclude a high differential rotation for its fast-rotating (P$, Comment: 20 pages, 15 figures, accepted for publication in A&A on 19 December 2019

Published
2020

38. A precise architecture characterization of the π Mensae planetary system

Author

Giorgio Pariani, A. Fragoso, Andrea Modigliani, Paolo Molaro, Yann Alibert, Jose Luis Rasilla, Giuseppina Micela, S. Santana Tschudi, David Ehrenreich, Antonino Bianco, Paolo Conconi, Hans Dekker, P. Figueira, Denis Mégevand, Luca Pasquini, Matteo Aliverti, B. Delabre, Filippo Maria Zerbi, T. Bandy, M. A. Monteiro, E. Mueller, R. Génova Santos, C. Maire, A. Suárez Mascareño, Edoardo Maria Alberto Redaelli, Manuel Abreu, Giorgio Calderone, Luca Oggioni, G. Avila, C. Allende Prieto, L. Genolet, Mahmoudreza Oshagh, Nelson J. Nunes, M. Affolter, Stéphane Udry, Vardan Adibekyan, Ennio Poretti, Alessandro Sozzetti, G. Lo Curto, David Alves, Danuta Sosnowska, Alexandre Cabral, Andrea Mehner, J. Knudstrup, Romain Allart, F. Tenegi, Nuno C. Santos, Stefano Cristiani, Marco Riva, Florian Kerber, José Manuel Rebordão, Rafael Rebolo, Olivier Demangeon, C. Lovis, Enric Palle, Damien Ségransan, I. Hughes, Mário J. P. F. G. Monteiro, Vincent Bourrier, J. I. González Hernández, G. Cupani, M. Amate, J. L. Lizon, Roberto Cirami, M. R. Zapatero Osorio, Antonio Gouveia Oliveira, Paolo Santin, João P. Faria, François Bouchy, Baptiste Lavie, S. G. Sousa, Hugo M. Tabernero, Willy Benz, D. Álvarez, Francesco Borsa, T. M. Schmidt, P. Di Marcantonio, Diego Bossini, Francesco Pepe, P. Spano, Pedro Santos, Marco Landoni, S. C. C. Barros, Xavier Dumusque, Olaf Iwert, Cristina Martins, Michael T. Murphy, V. Baldini, C. Broeg, Matteo Genoni, Claudio Cumani, A. Segovia, M. Moschetti, João Coelho, Valentina D'Odorico, Alessio Zanutta, S. Deiries, Igor Coretti, Jorge Lillo-Box, Mario Damasso, 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), Agenzia Spaziale Italiana (ASI), Fundação para a Ciência e a Tecnologia (FCT), Australian Research Council (ARC), Istituto Nazionale Astrofisica (INAF), Pallé, E. [0000-0003-0987-1593], Progetto Premiale 2015 FRONTIERA funding scheme of the Italian Ministry of Education University and Research, ESPRESSO through the SNSF 140649 152721 166227 184618 University and Research OB.FU. 1.05.06.11, SNSF's FLARE Programme, FEDER through COMPETE2020 -Programa Operacional Competitividade e Internacionalizacao UID/FIS/04434/2019 UIDB/04434/2020 UIDP/04434/2020 PTDC/FIS-AST/32113/2017 POCI-01-0145-FEDER-032113 PTDC/FIS-AST/28953/2017 POCI-01-0145-FEDER-028953 PTDC/FIS-AST/28987/2017 POCI-01-0145-FEDER-028987, Fundação para a Ciência e a Tecnologia (FCT) IF/01312/2014/CP1215/CT0004 IF/00650/2015/CP1273/CT0001 IF/00028/2014/CP1215/CT0002 DL 57/2016/CP1364/CT0005, Spanish Government, Ministerio de Ciencia e Innovación (MICINN) under the 2013 Ramon y Cajal program RYC-2013-14875, Australian Research Council, Istituto Nazionale Astrofisica (INAF) Agenzia Spaziale Italiana (ASI) n.2018-16-HH.0, and Unidad de Excelencia María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC

Subjects
Orbital plane, Brown dwarf, Orbital eccentricity, Context (language use), Astrophysics, 01 natural sciences, Planet, pi Men, individual: π Men [Stars], 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Stars: individual: π Men, radial velocities [Techniques], 010308 nuclear & particles physics, photometric [Techniques], individual: [stars], Astronomy and Astrophysics, Astrometry, Planetary system, Radial velocity, Planetary systems, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Techniques: radial velocities, Astrophysics::Earth and Planetary Astrophysics, Techniques: photometric, Astrophysics - Earth and Planetary Astrophysics
Abstract

Damasso, M. et al., Context. The bright star π Men was chosen as the first target for a radial velocity follow-up to test the performance of ESPRESSO, the new high-resolution spectrograph at the European Southern Observatory's Very Large Telescope. The star hosts a multi-planet system (a transiting 4 M· planet at ∼0.07 au and a sub-stellar companion on a ∼2100-day eccentric orbit), which is particularly suitable for a precise multi-technique characterization. Aims. With the new ESPRESSO observations, which cover a time span of 200 days, we aim to improve the precision and accuracy of the planet parameters and search for additional low-mass companions. We also take advantage of the new photometric transits of π Men c observed by TESS over a time span that overlaps with that of the ESPRESSO follow-up campaign. Methods. We analysed the enlarged spectroscopic and photometric datasets and compared the results to those in the literature. We further characterized the system by means of absolute astrometry with HIPPARCOS and Gaia. We used the high-resolution spectra of ESPRESSO for an independent determination of the stellar fundamental parameters. Results. We present a precise characterization of the planetary system around π Men. The ESPRESSO radial velocities alone (37 nightly binned data with typical uncertainty of 10 cm s-1) allow for a precise retrieval of the Doppler signal induced by π Men c. The residuals show a root mean square of 1.2 m s-1, which is half that of the HARPS data; based on the residuals, we put limits on the presence of additional low-mass planets (e.g. we can exclude companions with a minimum mass less than ∼2 M· within the orbit of π Men c). We improve the ephemeris of π Men c using 18 additional TESS transits, and, in combination with the astrometric measurements, we determine the inclination of the orbital plane of π Men b with high precision (ib =45.8-1.1+1.4 deg). This leads to the precise measurement of its absolute mass mb =14.1-0.4+0.5 MJup, indicating that π Men b can be classified as a brown dwarf. Conclusions. The π Men system represents a nice example of the extreme precision radial velocities that can be obtained with ESPRESSO for bright targets. Our determination of the 3D architecture of the π Men planetary system and the high relative misalignment of the planetary orbital planes put constraints on and challenge the theories of the formation and dynamical evolution of planetary systems. The accurate measurement of the mass of π Men b contributes to make the brown dwarf desert a bit greener., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

Published
2020

39. The SOPHIE search for northern extrasolar planets. XVI. HD 158259: A compact planetary system in a near-3:2 mean motion resonance chain

Author

Nuno C. Santos, Damien Ségransan, J.-B. Delisle, Xavier Dumusque, Xavier Bonfils, Gregory W. Henry, Flavien Kiefer, Francesco Pepe, Isabelle Boisse, Luc Arnold, B. Courcol, C. Moutou, Rodrigo F. Díaz, François Bouchy, Nathan Hara, M. Stalport, Olivier Demangeon, Simon Borgniet, T. Lopez, J. Rey, M. J. Hobson, B. Brugger, L. Mignon, S. Dalal, T. Forveille, Vincent Bourrier, Magali Deleuil, O. Mousis, P. A. Wilson, J. Rodrigues, X. Delfosse, Nicola Astudillo-Defru, Alexandre Santerne, Guillaume Hébrard, and Stéphane Udry

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Stellar rotation, FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, Planetary system, 01 natural sciences, Exoplanet, Radial velocity, Mean motion, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, 0103 physical sciences, Magnitude (astronomy), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for 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, Astrophysics - Earth and Planetary Astrophysics
Abstract

Since 2011, the SOPHIE spectrograph has been used to search for Neptunes and super-Earths in the Northern Hemisphere. As part of this observational program, 290 radial velocity measurements of the 6.4 V magnitude star HD 158259 were obtained. Additionally, TESS photometric measurements of this target are available. We present an analysis of the SOPHIE data and compare our results with the output of the TESS pipeline. The radial velocity data, ancillary spectroscopic indices, and ground-based photometric measurements were analyzed with classical and $\ell_1$ periodograms. The stellar activity was modeled as a correlated Gaussian noise and its impact on the planet detection was measured with a new technique. The SOPHIE data support the detection of five planets, each with $m \sin i \approx 6 M_\oplus$, orbiting HD 158259 in 3.4, 5.2, 7.9, 12, and 17.4 days. Though a planetary origin is strongly favored, the 17.4 d signal is classified as a planet candidate due to a slightly lower statistical significance and to its proximity to the expected stellar rotation period. The data also present low frequency variations, most likely originating from a magnetic cycle and instrument systematics. Furthermore, the TESS pipeline reports a significant signal at 2.17 days corresponding to a planet of radius $\approx 1.2 R_\oplus$. A compatible signal is seen in the radial velocities, which confirms the detection of an additional planet and yields a $\approx 2 M_\oplus$ mass estimate. We find a system of five planets and a strong candidate near a 3:2 mean motion resonance chain orbiting HD 158259. The planets are found to be outside of the two and three body resonances., Accepted for publication in Astronomy & Astrophysics

Published
2019

40. State of the Field: Extreme Precision Radial Velocities

Author

Debra A. Fischer, Guillem Anglada-Escude, Pamela Arriagada, Roman V. Baluev, Jacob L. Bean, Francois Bouchy, Lars A. Buchhave, Thorsten Carroll, Abhijit Chakraborty, Justin R. Crepp, Rebekah I. Dawson, Scott A. Diddams, Xavier Dumusque, Jason D. Eastman, Michael Endl, Pedro Figueira, Eric B. Ford, Daniel Foreman-Mackey, Paul Fournier, Gabor Fűrész, B. Scott Gaudi, Philip C. Gregory, Frank Grundahl, Artie P. Hatzes, Guillaume Hébrard, Enrique Herrero, David W. Hogg, Andrew W. Howard, John A. Johnson, Paul Jorden, Colby A. Jurgenson, David W. Latham, Greg Laughlin, Thomas J. Loredo, Christophe Lovis, Suvrath Mahadevan, Tyler M. McCracken, Francesco Pepe, Mario Perez, David F. Phillips, Peter P. Plavchan, Lisa Prato, Andreas Quirrenbach, Ansgar Reiners, Paul Robertson, Nuno C. Santos, David Sawyer, Damien Segransan, Alessandro Sozzetti, Tilo Steinmetz, Andrew Szentgyorgyi, Stéphane Udry, Jeff A. Valenti, Sharon X. Wang, Robert A. Wittenmyer, and Jason T. Wright

Published
2016
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41. A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system

Author

Damien Ségransan, Courtney D. Dressing, David W. Latham, Mia S. Lundkvist, John Asher Johnson, Valerio Nascimbeni, Torben Arentoft, Zoë M. Leinhardt, Christopher A. Watson, Ennio Poretti, Chantanelle Nava, Emilio Molinari, Francesco Pepe, Enrico Corsaro, Luca Malavolta, Aldo S. Bonomo, Xavier Dumusque, Michel Mayor, Li Zeng, Stéphane Udry, Thomas Denman, L. Affer, F. Bouchy, Mikkel N. Lund, Giuseppina Micela, Alessandro Sozzetti, Andrew Collier Cameron, Aldo F. M. Fiorenzano, Annelies Mortier, Savita Mathur, Dimitar Sasselov, Rasmus Handberg, Rafael A. García, Victor Silva Aguirre, Pedro Figueira, Eric D. Lopez, Sean M. Mills, Giampaolo Piotto, David F. Phillips, Hans Kjeldsen, Mercedes Lopez-Morales, Rosario Cosentino, Andrew Vanderburg, Ken Rice, Avet Harutyunyan, M. Benbakoura, Anders Bo Justesen, Jørgen Christensen-Dalsgaard, Lars A. Buchhave, Mario Damasso, C. Lovis, Fatemeh Motalebi, European Commission, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
OSCILLATION FREQUENCIES, astro-ph.SR, 010504 meteorology & atmospheric sciences, CODE, FOS: Physical sciences, Astrophysics, 01 natural sciences, Mantle (geology), Earth radius, HOT SUPER-EARTHS, LIMB-DARKENING COEFFICIENTS, chemistry.chemical_compound, Planet, 0103 physical sciences, QB Astronomy, 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), LIGHT CURVES, COMPANIONS, Astronomy and Astrophysics, 3rd-DAS, Radius, Exoplanet, Silicate, QC Physics, Astrophysics - Solar and Stellar Astrophysics, chemistry, 13. Climate action, CONVECTION, Extreme ultraviolet, astro-ph.EP, Terrestrial planet, STARS, Astrophysics - Earth and Planetary Astrophysics, PLANETS
Abstract

Measures of exoplanet bulk densities indicate that small exoplanets with radius less than 3 Earth radii ($R_\oplus$) range from low-density sub-Neptunes containing volatile elements to higher density rocky planets with Earth-like or iron-rich (Mercury-like) compositions. Such astonishing diversity in observed small exoplanet compositions may be the product of different initial conditions of the planet-formation process and/or different evolutionary paths that altered the planetary properties after formation. Planet evolution may be especially affected by either photoevaporative mass loss induced by high stellar X-ray and extreme ultraviolet (XUV) flux or giant impacts. Although there is some evidence for the former, there are no unambiguous findings so far about the occurrence of giant impacts in an exoplanet system. Here, we characterize the two innermost planets of the compact and near-resonant system Kepler-107. We show that they have nearly identical radii (about $1.5-1.6~R_\oplus$), but the outer planet Kepler-107c is more than twice as dense (about $12.6~\rm g\,cm^{-3}$) as the innermost Kepler-107b (about $5.3~\rm g\,cm^{-3}$). In consequence, Kepler-107c must have a larger iron core fraction than Kepler-107b. This imbalance cannot be explained by the stellar XUV irradiation, which would conversely make the more-irradiated and less-massive planet Kepler-107b denser than Kepler-107c. Instead, the dissimilar densities are consistent with a giant impact event on Kepler-107c that would have stripped off part of its silicate mantle. This hypothesis is supported by theoretical predictions from collisional mantle stripping, which match the mass and radius of Kepler-107c., Comment: Published in Nature Astronomy on 4 February 2019, 35 pages including Supplementary Information material

Published
2019

42. HD 213885b: A transiting 1-day-period super-Earth with an Earth-like composition around a bright ($V=7.9$) star unveiled by TESS

Author

Rafael Brahm, Caroline Dorn, Andrés Jordán, Christopher E. Henze, Jack J. Lissauer, Néstor Espinoza, Thomas Henning, Rhodes Hart, Olivier Demangeon, John F. Kielkopf, Eric L. N. Jensen, Andrei Tokovinin, Stéphane Udry, Sara Seager, Natalia Guerrero, J. Lillo-Box, Krzysztof G. Hełminiak, Benjamin F. Cooke, Oliver Turner, H. Giles, Nuno C. Santos, David W. Latham, Joshua N. Winn, Geof Wingham, Maxime Marmier, David Barrado, Damien Ségransan, Tansu Daylan, Patricia T. Boyd, Felipe Rojas, George R. Ricker, François Bouchy, John P. Doty, Martin Schlecker, P. Figueira, S. G. Sousa, Joseph D. Twicken, Karen A. Collins, Diana Kossakowski, Francesco Pepe, Peter J. Wheatley, David J. Armstrong, Matthew P. Battley, James S. Jenkins, Louise D. Nielsen, Daniel Bayliss, Vardan Adibekyan, Robert L. Morris, Aaron Dean Chacon, Ian J. M. Crossfield, Carl Ziegler, Matías R. Díaz, Claudia Aguilera-Gómez, Nicholas M. Law, Paula Sarkis, Jon M. Jenkins, C. Briceño, Christophe Lovis, S. C. C. Barros, Don Pollacco, Xavier Dumusque, Edward M. Bryant, Andrew W. Mann, Barrado, D. [https://orcid.org/0000-0002-5971-9242], Lillo Box, J. [https://orcid.org/0000-0003-3742-1987], Díaz, M. [https://orcid.org/0000-0002-2100-3257], Wheatley, P. [https://orcid.org/0000-0003-1452-2240], Nielsen, L. D. [https://orcid.org/0000-0002-5254-2499], Figueira, P. [https://orcid.org/0000-0001-8504-283X], Jenssen, E. [https://orcid.org/0000-0002-4625-7333], Barros, S. [https://orcid.org/0000-0003-2434-3625], Espinoza Pérez, N. [https://orcid.org/0000-0001-9513-1449], Armstrong, D. J. [https://orcid.org/0000-0002-5080-4117], Bayliss, D. [https://orcid.org/0000-0001-6023-1335], Turner, O. [https://orcid.org/0000-0002-8216-2796], Sousa, S. G. [https://orcid.org/0000-0001-9047-2965], Kielpof, J. F. [https://orcid.org/0000-0003-0497-2651], Comisión Nacional de Investigación Científica y Tecnológica (CONICYT), Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT), Science and Technology Facilities Council (STFC), Swiss National Science Foundation (SNSF), Fundacao para a Ciencia e a Tecnologia (FCT), National Science Centre, Poland (NCN), and Millennium Institute of Astrophysics (MAS)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, TOI-141, 010504 meteorology & atmospheric sciences, radial velocities [Techniques], photometric [Techniques], individual [Planets and satellites], FOS: Physical sciences, Astronomy and Astrophysics, TIC 403224672, HD213885, 01 natural sciences, detection [Planets and satellites], Space and Planetary Science, 0103 physical sciences, Christian ministry, dunfamental parameters [Planets and satellites], 85-XX, 010303 astronomy & astrophysics, Humanities, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

Espinoza, N. et al., We report the discovery of the 1.008-d, ultrashort period (USP) super-Earth HD 213885b (TOI-141b) orbiting the bright (V= 7.9) star HD 213885 (TOI-141, TIC 403224672), detected using photometry from the recently launched TESS mission. Using FEROS, HARPS, and CORALIE radial velocities, we measure a precise mass of 8.8 ±0.6M for this 1.74±0.05R exoplanet, which provides enough information to constrain its bulk composition - similar to Earth's but enriched in iron. The radius, mass, and stellar irradiation of HD 213885b are, given our data, very similar to 55 Cancri e, making this exoplanet a good target to perform comparative exoplanetology of short period, highly irradiated super-Earths. Our precise radial velocities reveal an additional 4.78-d signal which we interpret as arising from a second, non-transiting planet in the system, HD 213885c, whose minimum mass of 19.9 ± 1.4 M makes it consistent with being a Neptune-mass exoplanet. The HD 213885 system is very interesting from the perspective of future atmospheric characterization, being the second brightest star to host an USP transiting super-Earth (with the brightest star being, in fact, 55 Cancri). Prospects for characterization with present and future observatories are discussed., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

Published
2019

43. Hot, rocky and warm, puffy super-Earths orbiting TOI-402 (HD 15337)

Author

Sara Seager, Xavier Dumusque, Natalia Guerrero, Pamela Rowden, Joshua N. Winn, Vardan Adibekyan, Christopher E. Henze, Caroline Dorn, Rodrigo F. Díaz, Misty Davies, Stéphane Udry, Sérgio F. Sousa, David W. Latham, Jon M. Jenkins, Michel Mayor, Nuno C. Santos, Christoph Mordasini, C. Lovis, Damien Ségransan, Oliver Turner, A. Coffinet, Roland Vanderspek, Jason D. Eastman, François Bouchy, Romain Allart, Alejandro Suárez Mascareño, Michael Fausnaugh, Ana Glidden, Vincent Bourrier, George R. Ricker, Francesco Pepe, Elisa V. Quintana, and Joseph D. Twicken

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Orbital elements, 010504 meteorology & atmospheric sciences, 530 Physics, Exoplanetology, FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, Planetary system, Orbital period, 01 natural sciences, Exoplanet, Stars, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

TESS is revolutionising the search for planets orbiting bright and nearby stars. In sectors 3 and 4, TESS observed TOI-402 (TIC-120896927), a bright V=9.1 K1 dwarf also known as HD 15337, and found two transiting signals with period of 4.76 and 17.18 days and radius of 1.90 and 2.21\,\Rearth. This star was observed as part of the radial-velocity search for planets using the HARPS spectrometer, and 85 precise radial-velocity measurements were obtained over a period of 14 years. In this paper, we analyse the HARPS radial-velocity measurements in hand to confirm the planetary nature of these two signals. By reanalysing TESS photometry and host star parameters using EXOFASTv2, we find that TOI-402.01 and TOI-402.02 have periods of 4.75642$\pm$0.00021 and 17.1784$\pm$0.0016 days and radii of 1.70$\pm$0.06 and 2.52$\pm$0.11\,\Rearth\,(precision 3.6 and 4.2\%), respectively. By analysing the HARPS radial-velocity measurements, we find that those planets are both super-Earths with masses of 7.20$\pm$0.81 and 8.79$\pm$1.67\,\Mearth\,(precision 11.3 and 19.0\%), and small eccentricities compatible with zero at 2$\sigma$. Although having rather similar masses, the radius of these two planets is really different, putting them on different sides of the radius gap. With stellar irradiation 160 times more important than Earth for TOI-402.01 and only 29 times more for TOI-402.02, it is likely that photo-evaporation is at the origin of this radius difference. Those two planets, being in the same system and therefore being in the same irradiation environment are therefore extremely important to perform comparative exoplanetology across the evaporation valley and thus bring constraints on the mechanisms responsible for the radius gap., Comment: 25 pages, 16 figures, 6 tables, accepted in A&A

Published
2019

44. K2-291b: A Rocky Super-Earth in a 2.2 day Orbit

Author

Howard Isaacson, Makennah Bristow, A. Coffinet, Christopher A. Watson, Bronwen J. Hardee, Giuseppina Micela, David Phillips, Francesco Pepe, Alessandro Sozzetti, David R. Ciardi, Michel Mayor, F. Bouchy, Molly R. Kosiarek, Ian J. M. Crossfield, Stéphane Udry, Erica J. Gonzales, Joshua E. Schlieder, Sarah Blunt, Erik A. Petigura, Damien Ségransan, Courtney D. Dressing, Raphaëlle D. Haywood, Ennio Poretti, Chantanelle Nava, Ken Rice, Aldo S. Bonomo, Benjamin J. Fulton, Lea A. Hirsch, Christophe Lovis, Andrew W. Howard, Dimitar Sasselov, Lauren M. Weiss, Mario Damasso, Andrew Collier Cameron, Annelies Mortier, David W. Latham, Emilio Molinari, Lars A. Buchhave, Luca Malavolta, Pedro Figueira, Giampaolo Piotto, Mercedes Lopez-Morales, Andrew Vanderburg, Evan Sinukoff, David Charbonneau, Xavier Dumusque, European Commission, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, ITA, USA, GBR, DEU, and CHE

Subjects
planets and satellites: detection, 010504 meteorology & atmospheric sciences, detection [planets and satellites], FOS: Physical sciences, Astrophysics, 01 natural sciences, Planet, techniques: radial velocities, 0103 physical sciences, QB Astronomy, composition [planets and satellites], 010303 astronomy & astrophysics, QC, 0105 earth and related environmental sciences, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Super-Earth, planets and satellites: composition, Astronomy and Astrophysics, radial velocities [techniques], Radius, 3rd-DAS, Billion years, Photoevaporation, Radial velocity, Stars, QC Physics, 13. Climate action, Space and Planetary Science, astro-ph.EP, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract

K2-291 (EPIC 247418783) is a solar-type star with a radius of R_star = 0.899 $\pm$ 0.034 R_sun and mass of M_star=0.934 $\pm$ 0.038 M_sun. From K2 C13 data, we found one super-Earth planet (R_p = 1.589+0.095-0.072 R_Earth) transiting this star on a short period orbit (P = 2.225177 +6.6e-5 -6.8e-5 days). We followed this system up with adaptive-optic imaging and spectroscopy to derive stellar parameters, search for stellar companions, and determine a planet mass. From our 75 radial velocity measurements using HIRES on Keck I and HARPS-N on Telescopio Nazionale Galileo, we constrained the mass of EPIC 247418783b to M_p = 6.49 $\pm$ 1.16 M_Earth. We found it necessary to model correlated stellar activity radial velocity signals with a Gaussian process in order to more accurately model the effect of stellar noise on our data; the addition of the Gaussian process also improved the precision of this mass measurement. With a bulk density of 8.84+2.50-2.03 g cm-3, the planet is consistent with an Earth-like rock/iron composition and no substantial gaseous envelope. Such an envelope, if it existed in the past, was likely eroded away by photo-evaporation during the first billion years of the star's lifetime., Accepted to AJ, 15 pages, 8 figures

Published
2019

45. HARPS-N solar RVs are dominated by large, bright magnetic regions

Author

Giuseppina Micela, Rosario Cosentino, D. W. Latham, Adriano Ghedina, Heather M. Cegla, David F. Phillips, D. Charbonneau, Samantha Thompson, Steven H. Saar, Timothy Milbourne, C. H. Li, M. Lopez-Morales, Alessandro Sozzetti, C. Lovis, Andrew Szentgyorgyi, François Bouchy, Christopher A. Watson, M. Gonzalez, Stéphane Udry, Emilio Molinari, M. L. Palumbo, N. Buchschacher, Andrew Collier Cameron, Ken Rice, Jesus Maldonado, J. Costes, Francesco Pepe, Alex Glenday, Massimo Cecconi, L. Malavolta, Xavier Dumusque, Raphaëlle D. Haywood, D. Segransan, G. Piotto, M. Mayor, Annelies Mortier, Dimitar Sasselov, Nicholas Langellier, Ronald L. Walsworth, Marcello Lodi, 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, 010504 meteorology & atmospheric sciences, NDAS, faculae [Sun], Astrophysics, plages, 01 natural sciences, Sun: granulation, Planet, Sun: activity, 0103 physical sciences, techniques: radial velocities, Astrophysics::Solar and Stellar Astrophysics, QB Astronomy, activity [Sun], faculae, plages [Sun], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, QC, 0105 earth and related environmental sciences, QB, Physics, sunspots, Filling factor, Sunspots, radial velocities [techniques], Astronomy and Astrophysics, Sun: faculae, Light curve, Exoplanet, Solar telescope, Radial velocity, Stars, Photometry (astronomy), detection [Planets and satellites], QC Physics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Sun: faculae, plages, granulation [Sun], redial velocities [Techniques]
Abstract

State-of-the-art radial-velocity (RV) exoplanet searches are currently limited by RV signals arising from stellar magnetic activity. We analyze solar observations acquired over a 3 yr period during the decline of Carrington Cycle 24 to test models of RV variation of Sun-like stars. A purpose-built solar telescope at the High Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) provides disk-integrated solar spectra, from which we extract RVs and {log}{R}HK}{\prime }. The Solar Dynamics Observatory (SDO) provides disk-resolved images of magnetic activity. The Solar Radiation and Climate Experiment (SORCE) provides near-continuous solar photometry, analogous to a Kepler light curve. We verify that the SORCE photometry and HARPS-N {log}{R}HK}{\prime } correlate strongly with the SDO-derived magnetic filling factor, while the HARPS-N RV variations do not. To explain this discrepancy, we test existing models of RV variations. We estimate the contributions of the suppression of convective blueshift and the rotational imbalance due to brightness inhomogeneities to the observed HARPS-N RVs. We investigate the time variation of these contributions over several rotation periods, and how these contributions depend on the area of active regions. We find that magnetic active regions smaller than 60 Mm2 do not significantly suppress convective blueshift. Our area-dependent model reduces the amplitude of activity-induced RV variations by a factor of two. The present study highlights the need to identify a proxy that correlates specifically with large, bright magnetic regions on the surfaces of exoplanet-hosting stars.

Published
2019

46. The SOPHIE search for northern extrasolar planets XV. A Warm Neptune around the M-dwarf Gl378

Author

N. Cabrera Salazar, T. Forveille, S. Dalal, X. Delfosse, Flavien Kiefer, Rodrigo F. Díaz, C. Moutou, Stéphane Udry, Vincent Bourrier, Isabelle Boisse, Magali Deleuil, O. Mousis, Nicola Astudillo-Defru, Nuno C. Santos, M. J. Hobson, A. Santerne, Damien Ségransan, B. Courcol, L. Mignon, Xavier Dumusque, Xavier Bonfils, M. Stalport, Nathan Hara, S. Borgniet, P. A. Wilson, Luc Arnold, B. Brugger, Francesco Pepe, G. Hebrard, J. Rey, François Bouchy, Olivier Demangeon, T. Lopez, and G. Montagnier

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), Minimum mass, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Orbital period, 01 natural sciences, Exoplanet, 010309 optics, Radial velocity, Space and Planetary Science, Neptune, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Hot Neptune, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the detection of a Warm Neptune orbiting the M-dwarf Gl378, using radial velocity measurements obtained with the SOPHIE spectrograph at the Observatoire de Haute-Provence. The star was observed in the context of the SOPHIE exoplanets consortium's subprogramme dedicated to finding planets around M-dwarfs. Gl378 is an M1 star, of solar metallicity, at a distance of 14.96 pc. The single planet detected, Gl378 b, has a minimum mass of 13.02 $\rm M_{Earth}$ and an orbital period of 3.82 days, which place it at the lower boundary of the Hot Neptune desert. As one of only a few such planets around M-dwarfs, Gl378 b provides important clues to the evolutionary history of these close-in planets. In particular, the eccentricity of 0.1 may point to a high-eccentricity migration. The planet may also have lost part of its envelope due to irradiation., 10 pages, 8 figures, accepted for publication in A&A

Published
2019

47. Measuring precise radial velocities and cross-correlation function line-profile variations using a Skew Normal density

Author

Umberto Simola, Xavier Dumusque, Jessi Cisewski-Kehe, and Department of Mathematics and Statistics

Subjects
FOS: Computer and information sciences, STELLAR ACTIVITY, media_common.quotation_subject, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Asymmetry, Statistics - Applications, 0103 physical sciences, stars: activity, techniques: radial velocities, 111 Mathematics, Applications (stat.AP), Spurious relationship, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation), media_common, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Cross-correlation, STAR, 010308 nuclear & particles physics, Skew, COMPANIONS, Astronomy and Astrophysics, Function (mathematics), 115 Astronomy, Space science, methods: data analysis, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Skewness, Astrophysics - Earth and Planetary Astrophysics, PLANETS
Abstract

Context.Stellar activity is one of the primary limitations to the detection of low-mass exoplanets using the radial-velocity (RV) technique. Stellar activity can be probed by measuring time-dependent variations in the shape of the cross-correlation function (CCF). It is therefore critical to measure with high-precision these shape variations to decorrelate the signal of an exoplanet from spurious RV signals caused by stellar activity.Aims.We propose to estimate the variations in shape of the CCF by fitting a Skew Normal (SN) density which, unlike the commonly employed Normal density, includes a Skewness parameter to capture the asymmetry of the CCF induced by stellar activity and the convective blueshift.Methods.We compared the performances of the proposed method to the commonly employed Normal density using both simulations and real observations with different levels of activity and signal-to-noise ratios.Results.When considering real observations, the correlation between the RV and the asymmetry of the CCF and between the RV and the width of the CCF are stronger when using the parameters estimated with the SN density rather than those obtained with the commonly employed Normal density. In particular, the strongest correlations have been obtained when using the mean of the SN as an estimate for the RV. This suggests that the CCF parameters estimated using a SN density are more sensitive to stellar activity, which can be helpful when estimating stellar rotational periods and when characterizing stellar activity signals. Using the proposed SN approach, the uncertainties estimated on the RV defined as the median of the SN are on average 10% smaller than the uncertainties calculated on the mean of the Normal. The uncertainties estimated on the asymmetry parameter of the SN are on average 15% smaller than the uncertainties measured on the Bisector Inverse Slope Span (BIS SPAN), which is the commonly used parameter to evaluate the asymmetry of the CCF. We also propose a new model to account for stellar activity when fitting a planetary signal to RV data. Based on simple simulations, we were able to demonstrate that this new model improves the planetary detection limits by 12% compared to the model commonly used to account for stellar activity.Conclusions.The SN density is a better model than the Normal density for characterizing the CCF since the correlations used to probe stellar activity are stronger and the uncertainties of the RV estimate and the asymmetry of the CCF are both smaller.

Published
2019

48. HD219666b: A hot-Neptune from TESS Sector 1

Author

V. Van Eylen, J. N. Winn, Teriyuki Hirano, M. Esposito, D. L. Pollacco, Ignasi Ribas, J. de León, M. Tala-Pinto, David Nespral, H. J. Deeg, P. Figueira, S. Hojjatpanah, O. D. S. Demangeon, Grzegorz Nowak, M. Hjorth, John H. Livingston, Hugh P. Osborn, Farzana Meru, François Bouchy, William D. Cochran, Alexis M. S. Smith, S. C. C. Barros, Davide Gandolfi, Edward M. Bryant, Anders Erikson, N. C. Santos, Louise D. Nielsen, Michael Endl, Norio Narita, Vardan Adibekyan, Sascha Grziwa, K. W. F. Lam, D. Hidalgo, P. G. Beck, Duncan A. Brown, Peter J. Wheatley, Carina M. Persson, Mikkel N. Lund, Xavier Dumusque, Savita Mathur, A. P. Hatzes, Judith Korth, Anders Bo Justesen, Szilard Csizmadia, J. Prieto-Arranz, Fei Dai, J. Cabrera, Francesca Faedi, Rafael Luque, Emil Knudstrup, E. Delgado Mena, M. Pätzold, M. Fridlund, Oscar Barragán, Eike W. Guenther, J. Lillo-Box, Benjamin F. Cooke, Heike Rauer, Luca Fossati, Prajwal Niraula, S. Redfield, M. M. Musso, Patricio Cubillos, Roi Alonso, Rodrigo F. Díaz, Stéphane Udry, David Barrado, Enric Palle, A. S. Bonomo, P. Montanes Rodriguez, David J. Armstrong, Philipp Eigmüller, M. Deleuil, S. G. Sousa, D. Bayliss, A. Fukui, Laboratoire d'Astrophysique de Marseille (LAM), and 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)

Subjects
Dwarf star, 010504 meteorology & atmospheric sciences, fundamental parameters [Planets and satellites], FOS: Physical sciences, Astrophysics, Planets and satellites: individual: HD 219666 b, 01 natural sciences, fundamental parameters [Stars], Planet, 0103 physical sciences, Planets and satellites: detection, Planets and satellites: fundamental parameters, Stars: fundamental parameters, Techniques: photometric, Techniques: radial velocities, Hot Neptune, Spectroscopy, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), radial velocities [Techniques], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], photometric [Techniques], Astronomy and Astrophysics, Radius, Light curve, Orbital period, Exoplanet, detection [Planets and satellites], Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], individual: HD 219666 b [Planets and satellites], Astrophysics - Earth and Planetary Astrophysics
Abstract

We report on the confirmation and mass determination of a transiting planet orbiting the old and inactive G7 dwarf star HD219666 (Mstar = 0.92 +/- 0.03 MSun, Rstar = 1.03 +/- 0.03 RSun, tau_star = 10 +/- 2 Gyr). With a mass of Mb = 16.6 +/- 1.3 MEarth, a radius of Rb = 4.71 +/- 0.17 REarth, and an orbital period of P ~ 6 days, HD219666b is a new member of a rare class of exoplanets: the hot-Neptunes. The Transiting Exoplanet Survey Satellite (TESS) observed HD219666 (also known as TOI-118) in its Sector 1 and the light curve shows four transit-like events, equally spaced in time. We confirmed the planetary nature of the candidate by gathering precise radial-velocity measurements with HARPS@ESO3.6m. We used the co-added HARPS spectrum to derive the host star fundamental parameters (Teff = 5527 +/- 65 K, log g = 4.40 +/- 0.11 (cgs), [Fe/H]= 0.04 +/- 0.04 dex, log R'HK = -5.07 +/- 0.03), as well as the abundances of many volatile and refractory elements. The host star brightness (V = 9.9) makes it suitable for further characterisation by means of in-transit spectroscopy. The determination of the planet orbital obliquity, along with the atmospheric metal-to-hydrogen content and thermal structure could provide us with important clues on the formation mechanisms of this class of objects., Comment: Accepted for publication in A&A

Published
2019

49. Masses and radii for the three super-Earths orbiting GJ 9827, and implications for the composition of small exoplanets

Author

Andrew Collier Cameron, Annelies Mortier, Giuseppina Micela, E. Poretti, Ken Rice, Chantanelle Nava, Giampaolo Piotto, Luca Malavolta, Christopher A. Watson, Stéphane Udry, Li Zeng, F. Bouchy, Emilio Molinari, Alessandro Sozzetti, C. Lovis, Damien Ségransan, Andrew W. Mayo, Andrew Vanderburg, A. Coffinet, Lars A. Buchhave, A. S. Bonomo, Eric D. Lopez, Valerio Nascimbeni, Francesco Pepe, David W. Latham, A. F. Martinez Fiorenzano, M. Lopez-Morales, David F. Phillips, J. Asher Johnson, P. Figueira, David Charbonneau, Xavier Dumusque, M. Mayor, Mario Damasso, Laura Affer, Dimitar Sasselov, Raphaëlle D. Haywood, 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
Solar System, planets and satellites: detection, astro-ph.SR, Gas giant, fundamental parameters [Planets and satellites], Population, FOS: Physical sciences, Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, techniques: radial velocities, EPIC 246389858, QB Astronomy, education, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, radial velocities [Techniques], 010308 nuclear & particles physics, HIP 115752), planets and satellites: composition, Astronomy and Astrophysics, planets and satellites: general, 3rd-DAS, Stars: individual: GJ 9827 (2MASS J23270480-0117108, EPIC 246389858, HIP 115752), Photoevaporation, Exoplanet, general [Planets and satellites], Radial velocity, detection [Planets and satellites], QC Physics, Stars: individual: GJ 9827 (2MASS J23270480-0117108, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, composition [Planets and satellites], astro-ph.EP, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, individual: GJ 9827 (2MASS J23270480-0117108, EPIC 246389858, HIP 115752) [Stars], Astrophysics - Earth and Planetary Astrophysics
Abstract

Super-Earths belong to a class of planet not found in the Solar System, but which appear common in the Galaxy. Given that some super-Earths are rocky, while others retain substantial atmospheres, their study can provide clues as to the formation of both rocky planets and gaseous planets, and - in particular - they can help to constrain the role of photo-evaporation in sculpting the exoplanet population. GJ 9827 is a system already known to host 3 super-Earths with orbital periods of 1.2, 3.6 and 6.2 days. Here we use new HARPS-N radial velocity measurements, together with previously published radial velocities, to better constrain the properties of the GJ 9827 planets. Our analysis can't place a strong constraint on the mass of GJ 9827 c, but does indicate that GJ 9827 b is rocky with a composition that is probably similar to that of the Earth, while GJ 9827 d almost certainly retains a volatile envelope. Therefore, GJ 9827 hosts planets on either side of the radius gap that appears to divide super-Earths into pre-dominantly rocky ones that have radii below $\sim 1.5 R_\oplus$, and ones that still retain a substantial atmosphere and/or volatile components, and have radii above $\sim 2 R_\oplus$. That the less heavily irradiated of the 3 planets still retains an atmosphere, may indicate that photoevaporation has played a key role in the evolution of the planets in this system., 16 pages, 9 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society

Published
2019

50. HARPS-N radial velocities confirm the low densities of the Kepler-9 planets

Author

David Charbonneau, A. Coffinet, Christopher A. Watson, David F. Phillips, M. Lopez-Morales, Giuseppina Micela, P. Figueira, Luca Malavolta, Annelies Mortier, Francesco Pepe, Alessandro Sozzetti, Luca Borsato, M. Mayor, Stéphane Udry, Emilio Molinari, Ken Rice, Ennio Poretti, David W. Latham, Xavier Dumusque, Andrew Collier Cameron, Lars A. Buchhave, Giampaolo Piotto, Rosario Cosentino, European Commission, 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
FOS: Physical sciences, fundamental parameters [Stars], individual: Kepler-9 [Stars], 01 natural sciences, Kepler, spectroscopic [Techniques], Fundamental parameters [Radial velocity - Stars], Planet, 0103 physical sciences, QB Astronomy, media_common.cataloged_instance, European union, 010303 astronomy & astrophysics, QC, QB, media_common, Earth and Planetary Astrophysics (astro-ph.EP), Physics, radial velocities [Techniques], 010308 nuclear & particles physics, Astronomy, Kepler-9 [Individual], Astronomy and Astrophysics, 3rd-DAS, QC Physics, Space and Planetary Science, astro-ph.EP, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We investigated the discrepancy between planetary mass determination using the transit timing variations (TTVs) and radial velocities (RVs), by analysing the multi-planet system Kepler-9. Despite being the first system characterised with TTVs, there are several discrepant solutions in the literature, with those reporting lower planetary densities being apparently in disagreement with high-precision RV observations. To resolve this, we gathered HARPS-N RVs at epochs that maximised the difference between the predicted RV curves from discrepant solutions in the literature. We also re-analysed the full Kepler data-set and performed a dynamical fit, within a Bayesian framework, using the newly derived central and duration times of the transits. We compared these results with the RV data and found that our solution better describes the RV observations, despite the masses of the planets being nearly half that presented in the discovery paper. We therefore confirm that the TTV method can provide mass determinations that agree with those determined using high-precision RVs. The low densities of the planets place them in the scarcely populated region of the super-Neptunes / inflated sub-Saturns in the mass-radius diagram., 11 pages, 9 figures, 5 tables. Accepted for publication in MNRAS

Published
2019

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