Discovery and characterization of two exoplanets orbiting the metal-poor, solar-type star TOI-5788 with TESS, CHEOPS , and HARPS-N
Year: 2026
Type: article
Abstract: ABSTRACT We present the discovery and characterization of two transiting exoplanets orbiting the metal-poor, solar-type star TOI-5788. From our analysis of six TESS sectors and a dedicated CHEOPS programme, we identify an inner planet (TOI-5788 b; $P = 6.340758\pm 0.000030\, d$) with radius $1.528\pm 0.075\, \mathrm{R_{\oplus }}$ and an outer planet (TOI-5788 c; $P = 16.213362\pm 0.000026\, d$) with radius $2.272\pm 0.039\, \mathrm{R_{\oplus }}$. We obtain 125 radial-velocity spectra from HARPS-N and constrain the masses of TOI-5788 b and c as $3.72\pm 0.94\, \mathrm{M_{\oplus }}$ and $6.4\pm 1.2\, \mathrm{M_{\oplus }}$, respectively. Although dynamical analyses indicate that a third planet could exist in a stable orbit between 8 and 14 d, we find no evidence of additional planets. Since the TOI-5788 system is one of the few systems with planets straddling the radius gap, and noting that there are even fewer such systems around metal-poor stars, it is a promising system to constrain planet formation theories. We therefore model the interior structures of both planets. We find that TOI-5788 b is consistent with being a rocky planet with almost no envelope, or having an atmosphere of a high mean molecular weight. We find that TOI-5788 c is consistent with both gas-dwarf and water-world hypotheses of mini-Neptune formation. We model the atmospheric evolution history of both planets. While both scenarios are consistent with the atmospheric evolution of TOI-5788 c, the gas-dwarf model is marginally preferred. The results of the atmospheric evolution analysis are not strongly dependent on stellar evolution. This makes the system a promising target to test internal structure and atmospheric evolution models.
Authors: Ben S Lakeland, A Mortier, R D Haywood, S Ulmer-Moll, Z Garai, A Vanderburg, J A Egger, D A Turner, D Kubyshkina, A C M Correia, H P Osborn, L A Buchhave, L Malavolta, A Bonfanti, W Boschin, A Cameron, A Castro-González, R Cosentino, M Damasso, X Dumusque, D Ehrenreich, Z Essack, S Filomeno, L Fossati, D Gandolfi, M Gillon, C Hedges, M López-Morales, G Lacedelli, M Lendl, J Maldonado, G Mantovan, A F Martínez Fiorenzano, P F L Maxted, C Mordasini, B Nicholson, S M O’Brien, L Palethorpe, E Palle, M Pinamonti, D Rapetti, I Ribas, N C Santos, A M Silva, A Sozzetti, M Stalport, G Szabó, S Udry, M Vezie, C A Watson, T G Wilson
Institutions: University of Exeter, University of Birmingham, Leiden University, University of Liège, Leiden Observatory, Eötvös Loránd University, Slovak Academy of Sciences, Astronomical Institute of the Slovak Academy of Sciences, Center for Astrophysics Harvard & Smithsonian, University of Bern, European Space Agency, European Space Research and Technology Centre, Austrian Academy of Sciences, Space Research Institute, Centro de Física da Universidade de Coimbra, University of Coimbra, ETH Zurich, Center for Space and Habitability, DTU Space, Technical University of Denmark, University of Padua, Osservatorio Astronomico di Padova, University of St Andrews, University of Geneva, Osservatorio Astrofisico di Catania, Osservatorio Astrofisico di Torino, University of New Mexico, University of Rome Tor Vergata, Astronomical Observatory of Rome, Sapienza University of Rome, National Institute for Astrophysics, University of Turin, Goddard Space Flight Center, Space Telescope Science Institute, Universidad de La Laguna, Instituto de Astrofísica de Canarias, Osservatorio Astronomico di Palermo, Keele University, University of Southern Queensland, Queen's University Belfast, Royal Observatory, University of Edinburgh, Ames Research Center, Universities Space Research Association, Research Institute for Advanced Computer Science, Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, Universidade do Porto, Institute of Astrophysics and Space Sciences, Centro de Astrofísica da Universidade do Porto, Massachusetts Institute of Technology, University of Warwick
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
Funders: National Science Foundation, National Aeronautics and Space Administration, Society of Surgical Oncology, Entomological Society of America, California Institute of Technology, Fondazione CRT, Space Telescope Science Institute, Ukrainian Research Institute, Harvard University, UK Research and Innovation, Diabetes Patient Advocacy Coalition, European Space Agency, Scottish Universities Physics Alliance, University of St Andrews, European Commission, Queen's University Belfast, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Austrian Science Fund, Fonds De La Recherche Scientifique - FNRS, Belgian Federal Science Policy Office, Queen's University, Ministerio de Ciencia e Innovación, Mitutoyo Association for Science and Technology, Agentúra na Podporu Výskumu a Vývoja, Vedecká Grantová Agentúra MŠVVaŠ SR a SAV, Université de Genève, Eötvös Loránd Tudományegyetem, Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, National Academy of Sciences, Ames Research Center, Institut sur la Nutrition et les Aliments Fonctionnels, Smithsonian Astrophysical Observatory, Science and Technology Facilities Council, Fundação para a Ciência e a Tecnologia, European Regional Development Fund, Agencia Estatal de Investigación, Division of Chemistry, H2020 European Research Council
Awards: G1089506725, G1129048233, G121809054, G1353885700, G1382750735, TITANIA: TIme variabiliTy As a New window on exoplanet clImAtes, G1622782223, G1646535634, G1648110521, G1785165012, Spectroscopy of hot twilights in exoplanetary atmospheres, G1839585985, G1900605764, G195395952, G2065392807, G229093490, G2309174360, G2313451655, G2499501003, G2660406951, G2849677938, G2959288397, G302750986, G308504231, Centro de Física da Universidade de Coimbra, G3161872288, Instituto de Astrofísica e Ciências do Espaço, Instituto de Astrofísica e Ciências do Espaço, Instituto de Astrofísica e Ciências do Espaço, G3439265645, G344414887, G3480869486, G3518538256, G368632804, G3782671888, Formation and Evolution of Planets orbiting Low-mass Stars, G3909124325, G4034668834, Anomálne zatmenia a tranzity nebeských telies, G4276578120, G441095050, G4526231891, G464105488, G4655338613, Does ensemble decorrelation in the olfactory bulb predict odor discrimination behavior?, G4780359322, G4881816674, From oscillations to rotation: Detecting exoplanets through BiSON, G5080475149, G5385376234, G5565304244, G5707668056, G5811562009, G5845768719, G617610489, G6180974586, G6298322667, G6462632106, G6489768745, G6508622221, G6625920055, NCCR PlanetS: Origin, evolution and characterisation of planets, G6905238488, G6925629062, Savoirs, pouvoirs et gouvernement des esprits: Qui contrôle l'enseignement et la formation ?, G6997658380, G7075130942, G7084143925, G7127860775, Centro de Física da Universidade de Coimbra, A stellar revolution to characterise small planets and discover other Earths, G7255674937, G7321246223, G7434936867, G7476612352, G7727217969, G7783453933, G7858962851, G8175129975, 'Inventors of New Things': An Entangled History of Art in Antwerp, circa 1600, G8308124115, G8318038168, Characterization of the expression of Retinoic acid receptor during early chick development, G8505061131, G8874813653, G897484643, Matéria escura e metais nas galáxias (DarkMAGE)
OpenAlex ID: W7125399292