A planetary system with a sub-Neptune planet in the habitable zone of TOI-2093
Aims . We aim to confirm and measure the mass of the transiting planet candidate around the K5 V star TOI-2093, previously announced by the Transiting Exoplanet Survey Satellite (TESS) project. Methods . We combined photometric data from 32 sectors between 2019 and 2024 with 86 radial velocity measurements obtained with the CARMENES spectrograph over a period of 2.4 years, along with a series of ground-based, broadband photometric monitoring campaigns to characterize the host star and the transiting planet candidate, as well as to search for additional planets in the system. Our data indicate that TOI-2093 is a main-sequence star located at a distance of 83 pc, with solar metallicity, and a rotation period of 43.8±1.8 d. Results . We have confirmed the planetary nature of the TESS transiting planet candidate, named TOI-2093 c, through the detection of its Keplerian signal in the spectroscopic data. We measured a planetary radius of 2.30±0.12 R ⊕ , a Neptune-like mass of 15.8 −3.8 +3.6 M ⊕ , and an orbital period of 53.81149±0.00017 d. This makes TOI-2093 c the smallest exoplanet known in the habitable zone of a main-sequence FGK star. Given its size and relatively high density, TOI-2093 c belongs to a class of planets with no analog in the Solar System. In addition, the CARMENES data revealed the presence of a second planet candidate with a minimum mass of 10.6±2.5 M ⊕ and an orbital period of 12.836±0.021 d. This inner planet, which we designated TOI-2093 b, shows no detectable photometric transit in the TESS light curves. The orbital planes of the two planets are misaligned by more than 1.6° despite the near 4:1 mean-motion resonance of their orbital periods.
Authors
- A. Reiners (ORCID: https://orcid.org/0000-0003-1242-5922)
- A. Schweitzer
- M. Błażek (ORCID: https://orcid.org/0000-0003-0034-7891)
- F. Murgas
- E. Nagel
- S. Vanaverbeke (ORCID: https://orcid.org/0000-0003-0231-2676)
- F. J. Pozuelos (ORCID: https://orcid.org/0000-0003-1572-7707)
- D.W. Latham
- Ε. Πάλλη (ORCID: https://orcid.org/0000-0003-0987-1593)
- M. R. Zapatero Osorio (ORCID: https://orcid.org/0000-0001-5664-2852)
- J. A. Caballero (ORCID: https://orcid.org/0000-0002-7349-1387)
- P. J. Amado (ORCID: https://orcid.org/0000-0002-8388-6040)
- C. López (ORCID: https://orcid.org/0000-0001-5559-7850)
- E. Marfil
- I. Carleo
- K. R. Sreenivas (ORCID: https://orcid.org/0000-0003-3450-0372)
- A. P. Hatzes (ORCID: https://orcid.org/0000-0002-3404-8358)
- I. Ribas (ORCID: https://orcid.org/0000-0002-6689-0312)
- V. J. S. Béjar (ORCID: https://orcid.org/0000-0002-5086-4232)
- R.P. Schwarz
- D. Montes (ORCID: https://orcid.org/0000-0002-7779-238X)
- L. Tal-Or (ORCID: https://orcid.org/0000-0003-3757-1440)
- K. Collins
- David Rapetti (ORCID: https://orcid.org/0000-0003-2196-6675)
- E. Herrero (ORCID: https://orcid.org/0000-0001-8602-6639)
- G. Nowak
- Juan Carlos Morales (ORCID: https://orcid.org/0000-0003-2400-405X)
- David R. Ciardi (ORCID: https://orcid.org/0000-0002-5741-3047)
- S. Reffert
- E. González-Álvarez (ORCID: https://orcid.org/0000-0002-4820-2053)
- C. Cifuentes (ORCID: https://orcid.org/0000-0003-1715-5087)
- J. Lillo-Box
- A. Quirrenbach (ORCID: https://orcid.org/0000-0002-3302-1962)
- R. Luque
- Th. Henning
- J. Sanz‐Forcada (ORCID: https://orcid.org/0000-0002-1600-7835)
Institutions
- Universidad Complutense de Madrid (ES)
- Ames Research Center (US)
- The University of Sydney (AU)
- Universities Space Research Association (US)
- Universidad de La Laguna (ES)
- Heidelberg University (DE)
- NASA Exoplanet Science Institute (US)
- University of Chicago (US)
- Calar Alto Observatory (ES)
- Institute of Astrophysics and Space Sciences (PT)
- Institut d'Estudis Espacials de Catalunya (ES)
- Max Planck Institute for Astrophysics (DE)
- Osservatorio Astrofisico di Torino (IT)
- Max Planck Institute for Astronomy (DE)
- Institute of Space Sciences (ES)
- Institute of Astronomy (RU)
- Center for Astrophysics Harvard & Smithsonian (US)
- Centro de Astrobiología (ES)
- Instituto de Astrofísica de Canarias (ES)
- Nicolaus Copernicus Astronomical Center (PL)
- Research Institute of Geodesy, Topography and Cartography (CZ)
- Hamburger Fern-Hochschule (DE)
- Thüringer Landessternwarte Tautenburg (DE)
- Instituto de Astrofísica de Andalucía (ES)
- Stichting tot Steun VCVGZ (NL)
- Ariel University (IL)
- Netherlands Institute for Radio Astronomy (NL)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2025-09-30
- DOI
- https://doi.org/10.1051/0004-6361/202556361
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00