2002/10/11 by Melanie Freed, Laird M. Close, Nick Siegler
Physics and Astronomy · Social Sciences · #Astronomy and Astrophysical Research #Blue dwarf #Brown dwarf #Educational Leadership and Practices #Low Mass #Photometry (optics) #Primary (astronomy) #Proper motion #Stellar classification #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/345533
published as Astrophys.J. 584 (2003) 453-458 · 17 pages, 3 figures, Accepted for publication in the Astrophysical Journal
arxiv created 2002/10/11 · openalex publication_date 2003/02/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.