Abstract
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 language | English (US) |
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Pages (from-to) | 453-458 |
Number of pages | 6 |
Journal | Astrophysical Journal |
Volume | 584 |
Issue number | 1 I |
DOIs | |
State | Published - Feb 10 2003 |
Keywords
- 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