Populating the brown dwarf and stellar boundary: Five stars with transiting companions near the hydrogen-burning mass limit

Grieves, Nolan and Bouchy, Francois and Lendl, Monika and Carmichael, Theron and Mireles, Ismael and Shporer, Avi and McLeod, Kim K. and Collins, Karen A. and Brahm, Rafael and Stassun, Keivan G. and Gill, Sam and Bouma, Luke G. and Guillot, Tristan and Cointepas, Marion and Dos Santos, Leonardo A. and Casewell, Sarah L. and Jenkins, Jon M. and Henning, Thomas and Nielsen, Louise D. and Psaridi, Angelica and Udry, Stephane and Segransan, Damien and Eastman, Jason D. and Zhou, George ORCID: https://orcid.org/0000-0002-4891-3517 and Abe, Lyu and Agabi, Abelkrim and Bakos, Gaspar and Charbonneau, David and Collins, Kevin I. and Colon, Knicole D. and Crouzet, Nicolas and Dransfield, Georgina and Evans, Phil and Goeke, Robert F. and Hart, Rhodes and Irwin, Jonathan M. and Jensen, Eric L. N. and Jordan, Andres and Kielkopf, John F. and Latham, David W. and Marie-Sainte, Wenceslas and Mekarnia, Djamel and Nelson, Peter and Quinn, Samuel N. and Radford, Don J. and Rodriguez, David R. and Rowden, Pamela and Schmider, Francois-Xavier and Schwarz, Richard P. and Smith, Jeffrey C. and Stockdale, Chris and Suarez, Olga and Tan, Thiam-Guan and Triaud, Amaury H. M. J. and Waalkes, William and Wingham, Geof (2021) Populating the brown dwarf and stellar boundary: Five stars with transiting companions near the hydrogen-burning mass limit. Astronomy and Astrophysics, 652:A127. pp. 1-25. ISSN 0004-6361


Abstract

We report the discovery of five transiting companions near the hydrogen-burning mass limit in close orbits around main sequence stars originally identified by the Transiting Exoplanet Survey Satellite (TESS) as TESS objects of interest (TOIs): TOI-148, TOI-587, TOI-681, TOI-746, and TOI-1213. Using TESS and ground-based photometry as well as radial velocities from the CORALIE, CHIRON, TRES, and FEROS spectrographs, we found the companions have orbital periods between 4.8 and 27.2 days, masses between 77 and 98 MJup, and radii between 0.81 and 1.66 RJup. These targets have masses near the uncertain lower limit of hydrogen core fusion (~73-96 MJup), which separates brown dwarfs and low-mass stars. We constrained young ages for TOI-587 (0.2 ± 0.1 Gyr) and TOI-681 (0.17 ± 0.03 Gyr) and found them to have relatively larger radii compared to other transiting companions of a similar mass. Conversely we estimated older ages for TOI-148 and TOI-746 and found them to have relatively smaller companion radii. With an effective temperature of 9800 ± 200 K, TOI-587 is the hottest known main-sequence star to host a transiting brown dwarf or very low-mass star. We found evidence of spin-orbit synchronization for TOI-148 and TOI-746 as well as tidal circularization for TOI-148. These companions add to the population of brown dwarfs and very low-mass stars with well measured parameters ideal to test formation models of these rare objects, the origin of the brown dwarf desert, and the distinction between brown dwarfs and hydrogen-burning main sequence stars.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Astrophysics (1 Aug 2018 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Astrophysics (1 Aug 2018 -)
Date Deposited: 02 Mar 2022 04:58
Last Modified: 24 Oct 2022 23:20
Uncontrolled Keywords: Binaries: Eclipsing; Brown dwarfs; Stars: Low-mass; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
Funding Details:
Identification Number or DOI: https://doi.org/10.1051/0004-6361/202141145
URI: http://eprints.usq.edu.au/id/eprint/44989

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