Astrometric orbits of spectral binary brown dwarfs - I. Massive T dwarf companions to 2M1059-21 and 2M0805+48 - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Monthly Notices of the Royal Astronomical Society Year : 2020

Astrometric orbits of spectral binary brown dwarfs - I. Massive T dwarf companions to 2M1059-21 and 2M0805+48

J. Sahlmann
A. J. Burgasser
  • Function : Author
D. C. Bardalez Gagliuffi
  • Function : Author
P. F. Lazorenko
  • Function : Author
D. Ségransan
  • Function : Author
M. R. Zapatero Osorio
  • Function : Author
C. H. Blake
  • Function : Author
C. R. Gelino
  • Function : Author
E. L. Martín
  • Function : Author

Abstract

Near-infrared spectroscopic surveys have uncovered a population of short-period, blended-light spectral binaries composed of low-mass stars and brown dwarfs. These systems are amenable to orbit determination and individual mass measurements via astrometric monitoring. Here, we present first results of a multiyear campaign to obtain high-precision absolute astrometry for spectral binaries using the Gemini-South and Gemini-North GMOS imagers. We measure the complete astrometric orbits for two systems: 2M0805+48 and 2M1059-21. Our astrometric orbit of 2M0805+48 is consistent with its 2-yr radial velocity orbit determined previously and we find a mass of 66-14+5 MJup for its T5.5 companion. For 2M1059-21, we find a 1.9-yr orbital period and a mass of 67-5+4 MJup for its T3.5 companion. We demonstrate that sub-milliarcsecond absolute astrometry can be obtained with both GMOS imagers and that this is an efficient avenue for confirming and characterizing ultracool binary systems.
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insu-03678867 , version 1 (25-05-2022)

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J. Sahlmann, A. J. Burgasser, D. C. Bardalez Gagliuffi, P. F. Lazorenko, D. Ségransan, et al.. Astrometric orbits of spectral binary brown dwarfs - I. Massive T dwarf companions to 2M1059-21 and 2M0805+48. Monthly Notices of the Royal Astronomical Society, 2020, 495, pp.1136-1147. ⟨10.1093/mnras/staa1235⟩. ⟨insu-03678867⟩

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