Detalles de publicación
PP 024015
TESS and ESPRESSO discover a super-Earth and a mini-Neptune orbiting the K-dwarf TOI-238
(1) Instituto de Astrofísica de Canarias, (2) Departamento de Astrofísica, Universidad de La Laguna, (3) Hamburger Sternwarte, (4) Department of Physics, University of Warwick, (5) Centre for Exoplanets and Habitability, University of Warwick, (6) European Southern Observatory, (7) Observatoire astronomique de l’Université de Genève, (8) Instituto de Astrofísica e Ciências do Espaço, CAUP, Universidade do Porto, (9) Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, (10) Département de Physique, Institut Trottier de Recherche sur les Exoplanètes, Université de Montréal, (11) Consejo Superior de Investigaciones Científicas (CSIC), (12) INAF – Osservatorio Astronomico di Trieste, (13) INAF – Osservatorio Astrofisico di Torino, (14) Centro de Astrobiología, CSIC-INTA, (15) Departamento de Física de la Tierra y Astrofísica & IPARCOSUCM (Instituto de Física de Partículas y del Cosmos de la UCM), Facultad de Ciencias Físicas, Universidad Complutense de Madrid, (16) Physics Institute of University of Bern, (17) Scuola Normale Superiore, Piazza dei Cavalieri 7, (18) NASA Ames Research Center, (19) Center for Astrophysics - Harvard & Smithsonian, (20) Centro de Astrofísica da Universidade do Porto, (21) INAF - Osservatorio Astronomico di Palermo, (22) Instituto de Astrofísica e Ciências do EspaÇo, Faculdade de Ciências da Universidade de Lisboa, (23) Light Bridges S. L., (24) Royal Astronomical Society, (25) Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, (26) Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, (27) Department of Aeronautics and Astronautics, MIT, (28) Department of Astrophysical Sciences, Princeton University, (29) SETI Institute, (30) Società Astronomica Lunae
The number of super-Earth and mini-Neptune planet discoveries has increased significantly in the last two decades thanks to transit and radial velocity surveys. When it is possible to apply both techniques, we can characterise the internal composition of exoplanets, which in turn provides unique insights on their architecture, formation and evolution.
We performed a combined photometric and radial velocity analysis of TOI--238 (TYC 6398--132--1), which has one short-orbit super-Earth planet candidate announced by NASA's TESS team. We aim to confirm its planetary nature using radial velocities taken with the ESPRESSO and HARPS spectrographs, to measure its mass and to detect the presence of other possible planetary companions. We carried out a joint analysis by including Gaussian processes and Keplerian orbits to account for the stellar activity and planetary signals simultaneously.
We detected the signal induced by TOI-238 b in the radial velocity time-series, and the presence of a second transiting planet, TOI-238 c, whose signal appears in RV and TESS data. TOI-238 b is a planet with a radius of 1.402+0.084−0.086 R⊕ and a mass of 3.40+0.46−0.45 M⊕. It orbits at a separation of 0.02118 ± 0.00038 AU of its host star, with an orbital period of 1.2730988 ± 0.0000029 days, and has an equilibrium temperature of 1311 ± 28 K. TOI-238 c has a radius of 2.18± 0.18 R⊕ and a mass of 6.7 ± 1.1 M⊕. It orbits at a separation of 0.0749 ± 0.0013 AU of its host star, with an orbital period of 8.465652 ± 0.000031 days, and has an equilibrium temperature of 696 ± 15 K. The mass and radius of planet b are fully consistent with an Earth-like composition, making it likely a rocky super-Earth. Planet c could be a water-rich planet or a rocky planet with a small H-He atmosphere.
We performed a combined photometric and radial velocity analysis of TOI--238 (TYC 6398--132--1), which has one short-orbit super-Earth planet candidate announced by NASA's TESS team. We aim to confirm its planetary nature using radial velocities taken with the ESPRESSO and HARPS spectrographs, to measure its mass and to detect the presence of other possible planetary companions. We carried out a joint analysis by including Gaussian processes and Keplerian orbits to account for the stellar activity and planetary signals simultaneously.
We detected the signal induced by TOI-238 b in the radial velocity time-series, and the presence of a second transiting planet, TOI-238 c, whose signal appears in RV and TESS data. TOI-238 b is a planet with a radius of 1.402+0.084−0.086 R⊕ and a mass of 3.40+0.46−0.45 M⊕. It orbits at a separation of 0.02118 ± 0.00038 AU of its host star, with an orbital period of 1.2730988 ± 0.0000029 days, and has an equilibrium temperature of 1311 ± 28 K. TOI-238 c has a radius of 2.18± 0.18 R⊕ and a mass of 6.7 ± 1.1 M⊕. It orbits at a separation of 0.0749 ± 0.0013 AU of its host star, with an orbital period of 8.465652 ± 0.000031 days, and has an equilibrium temperature of 696 ± 15 K. The mass and radius of planet b are fully consistent with an Earth-like composition, making it likely a rocky super-Earth. Planet c could be a water-rich planet or a rocky planet with a small H-He atmosphere.