Discovery of a tight brown dwarf companion to the low-mass star LHS 2397a

Melante Freed, Laird M. Close, Nick Siegler

Research output: Contribution to journalReview articlepeer-review

50 Scopus citations


Using the adaptive optics system, Hokupa'a, at Gemini North, we have directly imaged a companion around the UKIRT faint standard M8 star LHS 2397a (FS 129) at a separation of 2.96 AU. Near-infrared photometry of the companion has shown it to be an L7.5 brown dwarf and confirmed the spectral type of the primary to be M8. We also derive a substellar mass of the companion of 0.068 M⊙, although masses in the range 0.061-0.069 M⊙ are possible, and the primary mass is 0.090 M⊙ (0.089-0.094 M⊙). Reanalysis of archival imaging from the Hubble Space Telescope has confirmed the secondary as a common proper motion object. This binary represents the first clear example of a brown dwarf companion within 4 AU of a low-mass star and should be one of the first late-L dwarfs to have a dynamical mass. As part of a larger survey of M8-L0 stars, this object may indicate that there is no "brown dwarf desert" around low-mass primaries.

Original languageEnglish (US)
Pages (from-to)453-458
Number of pages6
JournalAstrophysical Journal
Issue number1 I
StatePublished - Feb 10 2003


  • Binaries: general
  • Instrumentation: adaptive optics
  • Stars: evolution
  • Stars: formation
  • Stars: individual (LHS 2397a)
  • Stars: low-mass, brown dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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