A spectrqscopic binary at the M/L transition

Cullen H. Blake, David Charbonneau, Russel J. White, Guillermo Torres, Mark S. Marley, Didier Saumon

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


We report the discovery of a single-lined spectroscopic binary with an ultracool dwarf (UCD) primary with a spectral type between M8 and L0.5. This system was discovered during the course of an ongoing survey to monitor L dwarfs for radial velocity variations and is the first known small-separation (a < 1 AU) spectroscopic binary among dwarfs at the M/L transition. Based on radial velocity measurements with a typical precision of 300 m s-1, we estimate the orbital parameters of this system to be P = 246.73 ± 0.49 days, a1 sin i = 0.159 ± 0.003 AU, and M2 sin i = 0.2062(M1 + M2)2/3 ± 0.0034 M⊙. Assuming a primary mass of M1 = 0.08 M⊙ (based on spectral type), we estimate the secondary minimum mass to be M2 sin i = 0.054 M⊙. With future photometric, spectroscopic, and interferometric observations it may be possible to determine the dynamical masses of both components directly, making this system one of the best-characterized UCD binaries known.

Original languageEnglish (US)
Pages (from-to)L125-L128
JournalAstrophysical Journal
Issue number2 PART 2
StatePublished - 2008
Externally publishedYes


  • Brown dwarfs
  • Stars: low-mass
  • Techniques: radial velocities

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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