TOI 694b and TIC 220568520b: Two Low-mass Companions near the Hydrogen-burning Mass Limit Orbiting Sun-like Stars
Article
Article Title | TOI 694b and TIC 220568520b: Two Low-mass Companions near the Hydrogen-burning Mass Limit Orbiting Sun-like Stars |
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ERA Journal ID | 1048 |
Article Category | Article |
Authors | Mireles, Ismael (Author), Shporer, Avi (Author), Grieves, Nolan (Author), Zhou, George (Author), Gunther, Maximilian N. (Author), Brahm, Rafael (Author), Ziegler, Carl (Author), Stassun, Keivan G. (Author), Huang, Chelsea X. (Author), Nielsen, Louise (Author), Dos Santos, Leonardo A. (Author), Udry, Stephane (Author), Bouchy, Francois (Author), Ireland, Michael (Author), Wallace, Alexander (Author), Sarkis, Paula (Author), Henning, Thomas (Author), Jordan, Andres (Author), Law, Nicholas (Author), Mann, Andrew W. (Author), Paredes, Leonardo A. (Author), James, Hodari-Sadiki (Author), Jao, Wei-Chun (Author), Henry, Todd J. (Author), Butler, R. Paul (Author), Rodriguez, Joseph E. (Author), Yu, Liang (Author), Flowers, Erin (Author), Ricker, George R. (Author), Latham, David W. (Author), Vanderspek, Roland (Author), Seager, Sara (Author), Winn, Joshua N. (Author), Jenkins, Jon M. (Author), Furesz, Gabor (Author), Hesse, Katharine (Author), Quintana, Elisa V. (Author), Rose, Mark E. (Author), Smith, Jeffrey C. (Author), Tenenbaum, Peter (Author), Vezie, Michael (Author), Yahalomi, Daniel A. (Author) and Zhan, Zhuchang (Author) |
Journal Title | The Astronomical Journal |
Journal Citation | 160 (3), pp. 1-13 |
Article Number | 133 |
Number of Pages | 13 |
Year | 2020 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-6256 |
1538-3881 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/1538-3881/aba526 |
Web Address (URL) | https://iopscience.iop.org/article/10.3847/1538-3881/aba526 |
Abstract | We report the discovery of TOI 694 b and TIC 220568520 b, two low-mass stellar companions in eccentric orbits around metal-rich Sun-like stars, first detected by the Transiting Exoplanet Survey Satellite (TESS). TOI 694 b has an orbital period of 48.05131 ± 0.00019 days and eccentricity of 0.51946 ± 0.00081, and we derive a mass of 89.0 ± 5.3 MJup (0.0849 ± 0.0051 M⊙) and radius of 1.111 ± 0.017 RJup (0.1142 ± 0.0017 R⊙). TIC 220568520 b has an orbital period of 18.55769 ± 0.00039 days and eccentricity of 0.0964 ± 0.0032, and we derive a mass of 107.2 ± 5.2 MJup (0.1023 ± 0.0050 M⊙) and radius of 1.248 ± 0.018 RJup (0.1282 ± 0.0019 R⊙). Both binary companions lie close to and above the hydrogen-burning mass threshold that separates brown dwarfs and the lowest-mass stars, with TOI 694 b being 2σ above the canonical mass threshold of 0.075 M⊙. The relatively long periods of the systems mean that the magnetic fields of the low-mass companions are not expected to inhibit convection and inflate the radius, which according to one leading theory is common in similar objects residing in short-period tidally synchronized binary systems. Indeed we do not find radius inflation for these two objects when compared to theoretical isochrones. These two new objects add to the short but growing list of low-mass stars with well-measured masses and radii, and highlight the potential of the TESS mission for detecting such rare objects orbiting bright stars. |
Keywords | Low mass stars; M dwarf stars; Eclipsing binary stars; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | File reproduced in accordance with the copyright policy of the publisher/author. |
Institution of Origin | University of Southern Queensland |
Byline Affiliations | Massachusetts Institute of Technology, United States |
University of Geneva, Switzerland | |
Center for Astrophysics Harvard and Smithsonian, United States | |
Adolfo Ibanez University, Chile | |
University of Toronto, Canada | |
Vanderbilt University, United States | |
Australian National University | |
Max Planck Society, Germany | |
University of North Carolina, United States | |
Georgia State University, United States | |
United States Army Corps of Engineers Regional Economic Systems Institute, United States | |
Carnegie Institution of Washington, United States | |
Princeton University, United States | |
NASA Ames Research Center, United States | |
Wesleyan University, United States | |
NASA Goddard Space Flight Center, United States |
https://research.usq.edu.au/item/q6x54/toi-694b-and-tic-220568520b-two-low-mass-companions-near-the-hydrogen-burning-mass-limit-orbiting-sun-like-stars
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