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Alexander Mustill. Profile picture.

Alexander Mustill


Alexander Mustill. Profile picture.

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

Summary, in English

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=.55604±0.00016 days, a mass of Mb = 64.1±1.9 MJ, and a radius of Rb = 0.75±0.02 RJ. Its host star, TOI-569, has a mass of Må = 1.21±0.05 M, a radius of Rå = 1.47±0.03 R, [Fe H 0.29 0.09] = + dex, and an effective temperature of Teff = 5768±10K. TOI-1406b has an orbital period of P=10.57415±0.00063 days, a mass of Mb = 46.0± 2.7 MJ, and a radius of Rb = 0.86±0.03 RJ. The host star for this BD has a mass of Må = 1.18±0.09 M, a radius of Rå = 1.35±0.03 R, [Fe/H] =-0.08± 0.09 dex, and an effective temperature of Teff = 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 MJ 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.


  • Lund Observatory - Has been reorganised

Publishing year





The Astronomical Journal





Document type

Journal article


IOP Publishing


  • Astronomy, Astrophysics and Cosmology




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  • ISSN: 0004-6256