Discovery of a young low-mass brown dwarf transiting a fast-rotating F-type star by the Galactic Plane eXoplanet (GPX) survey. Issue 4 (31st May 2021)

• Record Type: Journal Article
• Authors: Benni, P; Burdanov, A Y; Krushinsky, V V; Bonfanti, A; Hébrard, G; Almenara, J M; Dalal, S; Demangeon, O D S; Tsantaki, M; Pepper, J; Stassun, K G; Vanderburg, A; Belinski, A; Kashaev, F; Barkaoui, K; Kim, T; Kang, W; Antonyuk, K; Dyachenko, V V; Rastegaev, D A; Beskakotov, A; Mitrofanova, A A; Pozuelos, F J; Kuznetsov, E D; Popov, A; Kiefer, F; Wilson, P A; Ricker, G; Vanderspek, R; Latham, D W; Seager, S; Jenkins, J M; Sokov, E; Sokova, I; Marchini, A; Papini, R; Salvaggio, F; Banfi, M; Baştürk, Ö; Torun, Ş; Yalçınkaya, S; Ivanov, K; Valyavin, G; Jehin, E; Gillon, M; Pakštienė, E; Hentunen, V-P; Shadick, S; Bretton, M; Wünsche, A; Garlitz, J; Jongen, Y; Molina, D; Girardin, E; Grau Horta, F; Naves, R; Benkhaldoun, Z; Joner, M D; Spencer, M; Bieryla, A; Stevens, D J; Jensen, E L N; Collins, K A; Charbonneau, D; Quintana, E V; Mullally, S E; Henze, C E;
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 505:Issue 4(2021)
• Page Start: 4956
• Page End: 4967
• Publication Date: 2021-05-31
• Subjects: stars: brown dwarfs -- stars: individual: GPX-1 -- stars: rotation -- surveys: Astronomical Data bases -- Galaxy: disc; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab1567
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We announce the discovery of GPX-1 b, a transiting brown dwarf with a mass of 19.7 ± 1.6 M Jup and a radius of 1.47 ± 0.10 R Jup, the first substellar 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 $v\sin {\, i_*}=40\pm 10$ km s −1 . We use the isochrone placement algorithm to characterize the host star, which has effective temperature 7000 ± 200 K, mass 1.68 ± 0.10 $\mathrm{\it M}_\odot$, radius 1.56 ± 0.10 $\mathrm{\it R}_\odot$, and approximate age $0.27_{-0.15}^{+0.09}$ Gyr. GPX-1 b has an orbital period of ∼1.75 d and a transit depth of 0.90 ± 0.03 per cent. 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 substellar object around the host star. GPX-1 was observed at 30-min integrations by TESS in Sector 18, but the data are 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 the Doppler tomography.