Substellar companions to main-sequence stars: No brown dwarf desert at wide separations

Citation
Je. Gizis et al., Substellar companions to main-sequence stars: No brown dwarf desert at wide separations, ASTROPHYS J, 551(2), 2001, pp. L163-L166
Citations number
27
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
551
Issue
2
Year of publication
2001
Part
2
Pages
L163 - L166
Database
ISI
SICI code
0004-637X(20010420)551:2<L163:SCTMSN>2.0.ZU;2-T
Abstract
We use three field L and T dwarfs that were discovered to be wide companion s to known stars by the Two Micron All-Sky Survey to derive a preliminary b rown dwarf companion frequency. Observed L and T dwarfs indicate that brown dwarfs are not unusually rare as wide (Delta > 1000 AU) systems to F-M0 ma in-sequence stars (M > 0.5 M., M-v < 9.5), even though they are rare at clo se separation (<Delta> < 3 AU; the "brown dwarf desert"). Stellar companion s in these separation ranges are equally frequent, but brown dwarfs are <gr eater than or similar to>10 times as frequent for wide than close separatio ns. A brown dwarf wide-companion frequency as low as the 0.5% seen in the b rown dwarf desert is ruled out by currently available observations.