ESPRESSO Mass determination of TOI-263b: An extreme inhabitant of the brown dwarf desert
| Autor: | Rafael Luque, V. S. J. Bejar, Hugo M. Tabernero, Hannu Parviainen, Enric Palle, Norio Narita, Mathias Zechmeister, M. R. Zapatero Osorio, Masahiro Ikoma, Alexander J. Mustill, Felipe Murgas |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Dwarf star
Brown dwarf FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Planet 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Substellar object 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics Earth and Planetary Astrophysics (astro-ph.EP) Physics 010308 nuclear & particles physics Astronomy and Astrophysics Planetary system Orbital period Radial velocity Stars Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science Astrophysics::Earth and Planetary Astrophysics Astrophysics - Earth and Planetary Astrophysics |
| Zdroj: | Astronomy & Astrophysics |
| Popis: | The TESS mission has reported a wealth of new planetary systems around bright and nearby stars amenable for detailed characterization of the planet properties and their atmospheres. However, not all interesting TESS planets orbit around bright host stars. TOI-263b is a validated ultra-short period substellar object in a 0.56-day orbit around a faint (V=18.97) M3.5 dwarf star. The substellar nature of TOI-263b was explored using multi-color photometry, which determined a true radius of 0.87+-0.21 Rj, establishing TOI-263b's nature ranging from an inflated Neptune to a brown dwarf. The orbital period-radius parameter space occupied by TOI-263b is quite unique, which prompted a further characterization of its true nature. Here, we report radial velocity measurements of TOI-263 obtained with 3 VLT units and the ESPRESSO spectrograph to retrieve the mass of TOI-263b. We find that TOI-263b is a brown dwarf with a mass of 61.6+-4.0 Mj. Additionally, the orbital period of the brown dwarf is found to be synchronized with the rotation period of the host star, and the system is found to be relatively active, possibly revealing a star--brown dwarf interaction. All these findings suggest that the system's formation history might be explained via disc fragmentation and later migration to close-in orbits. If the system is found to be unstable, TOI-263 is an excellent target to test the migration mechanisms before the brown dwarf becomes engulfed by its parent star. Accepted for Publication in Astronomy and Astrophysics |
| Databáze: | OpenAIRE |
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