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ESPRESSO mass determination of TOI-263b : An extreme inhabitant of the brown dwarf desert

Palle, E. ; Luque, R. ; Zapatero Osorio, M. R. ; Parviainen, H. ; Ikoma, M. ; Tabernero, H. M. ; Zechmeister, M. ; Mustill, A. J. LU orcid ; Bejar, V. S.J. and Narita, N. , et al. (2021) In Astronomy and Astrophysics 650.
Abstract

The TESS mission has reported a wealth of new planetary systems around bright and nearby stars amenable for detailed characterizations of planet properties and atmospheres. However, not all interesting TESS planets orbit around bright host stars. TOI-263 b is a validated ultra-short-period substellar object in a 0.56-day orbit around a faint (V = 18.97) M 3.5 dwarf star. The substellar nature of TOI-263 b was explored using multicolor photometry: a true radius of 0.87 ± 0.21 RJ was determined, establishing TOI-263 b 's nature as somewhere between an inflated Neptune and a brown dwarf. The orbital period-radius parameter space occupied by TOI-263 b is quite unique, which prompted a further characterization of its true nature. Here, we... (More)

The TESS mission has reported a wealth of new planetary systems around bright and nearby stars amenable for detailed characterizations of planet properties and atmospheres. However, not all interesting TESS planets orbit around bright host stars. TOI-263 b is a validated ultra-short-period substellar object in a 0.56-day orbit around a faint (V = 18.97) M 3.5 dwarf star. The substellar nature of TOI-263 b was explored using multicolor photometry: a true radius of 0.87 ± 0.21 RJ was determined, establishing TOI-263 b 's nature as somewhere between an inflated Neptune and a brown dwarf. The orbital period-radius parameter space occupied by TOI-263 b is quite unique, which prompted a further characterization of its true nature. Here, we report radial velocity measurements of TOI-263 obtained with three VLT units and the ESPRESSO spectrograph to retrieve the mass of TOI-263 b. We find that TOI-263 b is a brown dwarf with a mass of 61.6 ± 4.0 MJup. 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 disk fragmentation and a later migration to close-in orbits. If the system is found to be unstable, TOI-263 will be an excellent target to test the migration mechanisms before the brown dwarf becomes "engulfed"by its parent star.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Brown dwarfs, Instrumentation: spectrographs, Planets and satellites: formation, Planets and satellites: fundamental parameters, Planets and satellites: individual: TOI-263b, Techniques: radial velocities
in
Astronomy and Astrophysics
volume
650
article number
A55
publisher
EDP Sciences
external identifiers
  • scopus:85107590568
ISSN
0004-6361
DOI
10.1051/0004-6361/202039937
project
Consolidating CHEOPS and preparing for PLATO: Exoplanet studies in the 2020s
language
English
LU publication?
yes
id
7e139615-0efd-4998-a055-ae6a0b9a6eae
alternative location
https://arxiv.org/abs/2103.11150
date added to LUP
2021-06-29 10:07:18
date last changed
2023-02-21 11:22:02
@article{7e139615-0efd-4998-a055-ae6a0b9a6eae,
  abstract     = {{<p>The TESS mission has reported a wealth of new planetary systems around bright and nearby stars amenable for detailed characterizations of planet properties and atmospheres. However, not all interesting TESS planets orbit around bright host stars. TOI-263 b is a validated ultra-short-period substellar object in a 0.56-day orbit around a faint (V = 18.97) M 3.5 dwarf star. The substellar nature of TOI-263 b was explored using multicolor photometry: a true radius of 0.87 ± 0.21 RJ was determined, establishing TOI-263 b 's nature as somewhere between an inflated Neptune and a brown dwarf. The orbital period-radius parameter space occupied by TOI-263 b is quite unique, which prompted a further characterization of its true nature. Here, we report radial velocity measurements of TOI-263 obtained with three VLT units and the ESPRESSO spectrograph to retrieve the mass of TOI-263 b. We find that TOI-263 b is a brown dwarf with a mass of 61.6 ± 4.0 MJup. 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 disk fragmentation and a later migration to close-in orbits. If the system is found to be unstable, TOI-263 will be an excellent target to test the migration mechanisms before the brown dwarf becomes "engulfed"by its parent star. </p>}},
  author       = {{Palle, E. and Luque, R. and Zapatero Osorio, M. R. and Parviainen, H. and Ikoma, M. and Tabernero, H. M. and Zechmeister, M. and Mustill, A. J. and Bejar, V. S.J. and Narita, N. and Murgas, F.}},
  issn         = {{0004-6361}},
  keywords     = {{Brown dwarfs; Instrumentation: spectrographs; Planets and satellites: formation; Planets and satellites: fundamental parameters; Planets and satellites: individual: TOI-263b; Techniques: radial velocities}},
  language     = {{eng}},
  month        = {{06}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy and Astrophysics}},
  title        = {{ESPRESSO mass determination of TOI-263b : An extreme inhabitant of the brown dwarf desert}},
  url          = {{http://dx.doi.org/10.1051/0004-6361/202039937}},
  doi          = {{10.1051/0004-6361/202039937}},
  volume       = {{650}},
  year         = {{2021}},
}