Two Intermediate-mass Transiting Brown Dwarfs from the TESS Mission
Theron W. Carmichael, Samuel N. Quinn, Alexander J. Mustill, Chelsea Huang, George Zhou, Carina M. Persson, Louise D. Nielsen, Karen A. Collins, Carl Ziegler, Kevin I. Collins, Joseph E. Rodriguez, Avi Shporer, Rafael Brahm, Andrew W. Mann, Francois Bouchy, Malcolm Fridlund, Keivan G. Stassun, Coel Hellier, Julia V. Seidel, Manu Stalport, Stephane Udry, Francesco Pepe, Michael Ireland, Maruša Žerjal, César Briceño, Nicholas Law, Andrés Jordán, Néstor Espinoza, Thomas Henning, Paula Sarkis, David W. Latham
Abstract
Abstract We report the discovery of two intermediate-mass transiting brown dwarfs (BDs), TOI-569b and TOI-1406b, from NASA’s Transiting Exoplanet Survey Satellite mission. TOI-569b has an orbital period of P = 6.55604 ± 0.00016 days, a mass of M b = 64.1 ± 1.9 , and a radius of R b = 0.75 ± 0.02 . Its host star, TOI-569, has a mass of M ⋆ = 1.21 ± 0.05 , a radius of R ⋆ = 1.47 ± 0.03 , dex, and an effective temperature of T eff = 5768 ± 110 K. TOI-1406b has an orbital period of P = 10.57415 ± 0.00063 days, a mass of M b = 46.0 ± 2.7 , and a radius of R b = 0.86 ± 0.03 . The host star for this BD has a mass of M ⋆ = 1.18 ± 0.09 , a radius of R ⋆ = 1.35 ± 0.03 , dex, and an effective temperature of T eff = 6290 ± 100 K. Both BDs are in circular orbits around their host stars and are older than 3 Gyr based on stellar isochrone models of the stars. TOI-569 is one of two slightly evolved stars known to host a transiting BD (the other being KOI-415). TOI-1406b is one of three known transiting BDs to occupy the mass range of 40–50 and one of two to have a circular orbit at a period near 10 days (with the first being KOI-205b). Both BDs have reliable ages from stellar isochrones, in addition to their well-constrained masses and radii, making them particularly valuable as tests for substellar isochrones in the BD mass–radius diagram.