TOI-4438 b: a transiting mini-Neptune amenable to atmospheric characterization

Goffo, E. ; Chaturvedi, P. ; Murgas, F. ; Morello, G. ; Orell-Miquel, J. ; Acuña, L. ; Peña-Moñino, L. ; Pallé, E. ; Hatzes, A. P. ; Geraldía-González, S. ; Pozuelos, F. J. ; Lanza, A. F. ; Gandolfi, D. ; Caballero, J. A. ; Schlecker, M. ; Pérez-Torres, M. ; Lodieu, N. ; Schweitzer, A. ; Hellier, C. ; Jeffers, S. V. ; Duque-Arribas, C. ; Cifuentes, C. ; Béjar, V. J. S. ; Daspute, M. ; Dubois, F. ; Dufoer, S. ; Esparza-Borges, E. ; Fukui, A. ; Hayashi, Y. ; Herrero, E. ; Mori, M. ; Narita, N. ; Parviainen, H. ; Tal-Or, L. ; Vanaverbeke, S. ; Hermelo, I. ; Amado, P. J. ; Dreizler, S. ; Henning, Th. ; Lillo-Box, J. ; Luque, R. ; Mallorquín, M. ; Nagel, E. ; Quirrenbach, A. ; Reffert, S. ; Reiners, A. ; Ribas, I. ; Schöfer, P. ; Tabernero, H. M. ; Zechmeister, M.

Resumen: We report the confirmation and mass determination of a mini-Neptune transiting the M3.5 V star TOI-4438 (G 182-34) every 7.44 days. A transit signal was detected with NASA’s TESS space mission in the sectors 40, 52, and 53. In order to validate the planet TOI-4438 b and to determine the system properties, we combined TESS data with high-precision radial velocity measurements from the CARMENES spectrograph, spanning almost one year, and ground-based transit photometry. We found that TOI-4438 b has a radius of Rb = 2.52 ± 0.13 R⊕ (5% precision), which together with a mass of Mb = 5.4 ± 1.1 M⊕ (20% precision), results in a bulk density of ρb = 1.85−0.44+0.51 g cm−3 (~28% precision), aligning the discovery with a volatile-rich planet. Our interior structure retrieval with a pure water envelope yields aminimum water mass fraction of 46% (1σ). TOI-4438 b is a volatile-rich mini-Neptune with likely H/He mixed with molecules, such as water, CO2, and CH4. The primary star has a J-band magnitude of 9.7, and the planet has a high transmission spectroscopy metric (TSM) of 136 ± 13. Taking into account the relatively warm equilibrium temperature of Teq = 435 ± 15 K, and the low activity level of its host star, TOI-4438 b is one of the most promising mini-Neptunes around an M dwarf for transmission spectroscopy studies.

Idioma: Inglés

DOI: 10.1051/0004-6361/202349133

Año: 2024

Publicado en: Astronomy and Astrophysics 685, A147 (2024), 20
ISSN: 0004-6361

Factor impacto JCR: 5.8 (2024)

Categ. JCR: ASTRONOMY & ASTROPHYSICS rank: 16 / 84 = 0.19 (2024) - Q1 - T1

Factor impacto CITESCORE: 8.9 - Astronomy and Astrophysics (Q1) - Space and Planetary Science (Q1)

Factor impacto SCIMAGO: 1.968 - Space and Planetary Science (Q1) - Astronomy and Astrophysics (Q1)

Financiación: info:eu-repo/grantAgreement/ES/AEI/CEX2020-001058-M
Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2019-109522GB-C5
Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2021-125627OB-C31
Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2022-137241NB-C4
Financiación: info:eu-repo/grantAgreement/ES/MICINN/CEX2019-000920-S
Financiación: info:eu-repo/grantAgreement/ES/MICINN/CEX2021-001131-S
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2020-117404GB-C21
Financiación: info:eu-repo/grantAgreement/ES/MICINN PRE2020-095421

Tipo y forma: Artículo (Versión definitiva)