2008/04/09 by Cullen H. Blake, David Charbonneau, Russel J. White +5 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/588754
11 pages, 2 figures. Accepted for publication in ApJ Letters
arxiv created 2008/04/09 · openalex publication_date 2008/04/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
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, a 1 sin i = 0.159 ± 0.003 AU, and M 2 sin i = 0.2062( M 1 + M 2 ) 2/3 ± 0.0034 M ☉ . Assuming a primary mass of M 1 = 0.08 M ☉ (based on spectral type), we estimate the secondary minimum mass to be M 2 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.