1. Discovery of a young low-mass brown dwarf transiting a fast-rotating F-type star by the Galactic Plane eXoplanet (GPX) survey
- Author
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Andrew Vanderburg, F. Grau Horta, Eric L. N. Jensen, R. Naves, F. Kashaev, Michaël Gillon, W. Kang, Stan Shadick, Ş. Torun, V. V. Dyachenko, A. Bonfanti, A. Burdanov, Elisa V. Quintana, George R. Ricker, D. Molina, Olivier Demangeon, Francisco J. Pozuelos, Flavien Kiefer, Joshua Pepper, Sara Seager, M. Banfi, I. A. Sokova, A. A. Mitrofanova, A. Wunsche, V. Krushinsky, E. N. Sokov, Paul Wilson, Roland Vanderspek, Michael D. Joner, Chris Henze, Fabio Salvaggio, E. Pakštienė, E. Girardin, G. Valyavin, E. D. Kuznetsov, Guillaume Hébrard, A. Belinski, S. Dalal, David W. Latham, Keivan G. Stassun, J. Garlitz, D. A. Rastegaev, Özgür Baştürk, V.-P. Hentunen, A. Beskakotov, K. Antonyuk, Zouhair Benkhaldoun, Y. Jongen, T. Kim, M. Spencer, Emmanuel Jehin, Allyson Bieryla, Daniel J. Stevens, Karen A. Collins, Jose-Manuel Almenara, Susan E. Mullally, Alessandro Marchini, M. Bretton, David Charbonneau, A. A. Popov, M. Tsantaki, K. Ivanov, Jon M. Jenkins, Khalid Barkaoui, Riccardo Papini, Selçuk Yalçınkaya, and P. Benni
- Subjects
Brown dwarf ,ASTRONOMICAL DATA BASES [SURVEYS] ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Star (graph theory) ,ROTATION [STARS] ,01 natural sciences ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,INDIVIDUAL: GPX-1 [STARS] ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,DISC [GALAXY] ,Galactic plane ,BROWN DWARFS [STARS] ,Exoplanet ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Low Mass ,Astrophysics - Earth and Planetary Astrophysics - Abstract
We announce the discovery of GPX-1 b, a transiting brown dwarf with a mass of $19.7\pm 1.6$ $M_{\mathrm{Jup}}$ and a radius of $1.47\pm0.10$ $R_{\mathrm{Jup}}$, the first sub-stellar object discovered by the Galactic Plane eXoplanet (GPX) survey. The brown dwarf transits a moderately bright ($V$ = 12.3 mag) fast-rotating F-type star with a projected rotational velocity $v\sin{ i_*}=40\pm10$ km/s. We use the isochrone placement algorithm to characterize the host star, which has effective temperature $7000\pm200$ K, mass $1.68\pm0.10$ $M_{\mathrm{Sun}}$, radius $1.56\pm0.10$ $R_{\mathrm{Sun}}$ and approximate age $0.27_{-0.15}^{+0.09}$ Gyr. GPX-1 b has an orbital period of $\sim$1.75 d, and a transit depth of $0.90\pm0.03$ %. We describe the GPX transit detection observations, subsequent photometric and speckle-interferometric follow-up observations, and SOPHIE spectroscopic measurements, which allowed us to establish the presence of a sub-stellar object around the host star. GPX-1 was observed at 30-min integrations by TESS in Sector 18, but the data is affected by blending with a 3.4 mag brighter star 42 arcsec away. GPX-1 b is one of about two dozen transiting brown dwarfs known to date, with a mass close to the theoretical brown dwarf/gas giant planet mass transition boundary. Since GPX-1 is a moderately bright and fast-rotating star, it can be followed-up by the means of Doppler tomography., 13 pages, 13 figures, accepted to MNRAS in May 2021
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