TOI-2490b – the most eccentric brown dwarf transiting in the brown dwarf desert

ABSTRACT We report the discovery of the most eccentric transiting brown dwarf in the brown dwarf desert, TOI-2490b. The brown dwarf desert is the lack of brown dwarfs around main-sequence stars within $\sim 3$ au and is thought to be caused by differences in formation mechanisms between a star and planet. To date, only $\sim 40$ transiting brown dwarfs have been confirmed. TOI-2490b is a $73.6\pm 2.4$ $M_{\rm J}$, $1.00\pm 0.02$ $R_{\rm J}$ brown dwarf orbiting a $1.004_{-0.022}^{+0.031}$ ${\rm M}_{\odot }$, $1.105_{-0.012}^{+0.012}$ ${\rm R}_{\odot }$ sun-like star on a 60.33 d orbit with an eccentricity of $0.77989\pm 0.00049$. The discovery was detected within Transiting Exoplanet Survey Satellite sectors 5 (30 min cadence) and 32 (2 min and 20 s cadence). It was then confirmed with 31 radial velocity measurements with FEROS by the WINE collaboration and photometric observations with the Next Generation Transit Survey. Stellar modelling of the host star estimates an age of $\sim 8$ Gyr, which is supported by estimations from kinematics likely placing the object within the thin disc. However, this is not consistent with model brown dwarf isochrones for the system age suggesting an inflated radius. Only one other transiting brown dwarf with an eccentricity higher than 0.6 is currently known in the brown dwarf desert. Demographic studies of brown dwarfs have suggested such high eccentricity is indicative of stellar formation mechanisms.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2024-08-20
DOI
https://doi.org/10.1093/mnras/stae1940
Citations
7
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
2.32

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article

TOI-2490b – the most eccentric brown dwarf transiting in the brown dwarf desert

Maximiliano Moyano, Christina Hedges, J. McCormac, M. R. Burleigh et al.
7 citations
Monthly Notices of the Royal Astronomical Society
Stellar, planetary, and galactic studies
2.32
article

TOI-2490b – the most eccentric brown dwarf transiting in the brown dwarf desert

Maximiliano Moyano, Christina Hedges, J. McCormac, M. R. Burleigh, Jon M. Jenkins, Maximilian N. Günther, Marcelo Tala Pinto, R. G. West, M. Lendl, Edward Gillen, Katharine Hesse, Michael B. Lund, Daniel Bayliss, M. R. Goad, Diana Dragomir, D. J. Armstrong, Alicia Kendall, S. L. Casewell, Samuel Gill, J. S. Jenkins, Sara Seager, Gavin Ramsay, P. J. Wheatley, Ares Osborn, Andrés Jordán, David Rapetti, L. C. Mayorga, Jack S Acton, Beth A Henderson, Trifon Trifonov, José I Vines, D. R. Anderson, Suman Saha, Mélissa J. Hobson, S. Udry, Keivan G. Stassun, Ioannis Apergis, Tafadzwa Zivave, Thomas Henning, D. R. Alves, Rafael Brahm, Carl Ziegler, Joshua N. Winn
article en
7 citations

Abstract

ABSTRACT We report the discovery of the most eccentric transiting brown dwarf in the brown dwarf desert, TOI-2490b. The brown dwarf desert is the lack of brown dwarfs around main-sequence stars within $\sim 3$ au and is thought to be caused by differences in formation mechanisms between a star and planet. To date, only $\sim 40$ transiting brown dwarfs have been confirmed. TOI-2490b is a $73.6\pm 2.4$ $M_{\rm J}$, $1.00\pm 0.02$ $R_{\rm J}$ brown dwarf orbiting a $1.004_{-0.022}^{+0.031}$ ${\rm M}_{\odot }$, $1.105_{-0.012}^{+0.012}$ ${\rm R}_{\odot }$ sun-like star on a 60.33 d orbit with an eccentricity of $0.77989\pm 0.00049$. The discovery was detected within Transiting Exoplanet Survey Satellite sectors 5 (30 min cadence) and 32 (2 min and 20 s cadence). It was then confirmed with 31 radial velocity measurements with FEROS by the WINE collaboration and photometric observations with the Next Generation Transit Survey. Stellar modelling of the host star estimates an age of $\sim 8$ Gyr, which is supported by estimations from kinematics likely placing the object within the thin disc. However, this is not consistent with model brown dwarf isochrones for the system age suggesting an inflated radius. Only one other transiting brown dwarf with an eccentricity higher than 0.6 is currently known in the brown dwarf desert. Demographic studies of brown dwarfs have suggested such high eccentricity is indicative of stellar formation mechanisms.

Monthly Notices of the Royal Astronomical SocietyVol. 533(3)
University of Geneva (CH), California Institute of Technology (US), Ames Research Center (US), Goddard Space Flight Center (US), Universities Space Research Association (US), Research Institute for Advanced Computer Science (US), University of Leicester (GB), Queen Mary University of London (GB), University of New Mexico (US), Vanderbilt University (US), Princeton University (US), Stephen F. Austin State University (US), Adolfo Ibáñez University (CL), Heidelberg University (DE), Armagh Observatory & Planetarium (GB), NASA Exoplanet Science Institute (US), Universidad Católica del Norte (CL), Johns Hopkins University Applied Physics Laboratory (US), University of Warwick (GB), Millennium Institute of Astrophysics (CL), Max Planck Institute for Astronomy (DE), Centro de Astrofísica y Tecnologías Afines (CL), Data Observatory Foundation, European Space Research and Technology Centre (NL), American Institute of Aeronautics and Astronautics (US), Sofia University "St. Kliment Ohridski" (BG), Massachusetts Institute of Technology (US), University of Chile (CL), Universidad Diego Portales (CL)
National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Alfred P. Sloan Foundation, Princeton University, Ohio State University, California Institute of Technology, Johns Hopkins University, Universität Basel, New Mexico State University, UK Research and Innovation, European Space Agency, Deutsche Forschungsgemeinschaft, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Chinese Academy of Sciences, Bulgarian National Science Fund, Nuclear Safety and Security Commission, Max-Planck-Gesellschaft, European Southern Observatory, Agencia Nacional de Investigación y Desarrollo, Max-Planck-Institut für Astronomie, Ames Research Center, Science and Technology Facilities Council, Fondo Nacional de Desarrollo Científico y Tecnológico, Fermilab, Los Alamos National Laboratory
Openalex Percentile: Top 12%
Stellar, planetary, and galactic studies
2.32
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