New neighbours. III. 13 new companions to nearby dwarfs, discovered with adaptive optics
Abstract
We present some results of a CFHT adaptive optics search for companions to nearby dwarfs. We identify 13 new components in solar neighbourhood systems, of which 6 belong to a volume-limited sample of M dwarfs within 12 pc. We are obtaining complete observations for this subsample, to derive unbiased multiplicity statistics for the very-low-mass disk population. We additionally resolve for the first time 5 known spectroscopic or astrometric binaries, for a total of 18 newly resolved companions. A fair number of the new binaries has short enough estimated periods to offer good prospects for accurate mass determinations. The newly resolved companion of Gl~120.1C had an apparent spectroscopic minimum mass in the brown-dwarf range (Duquennoy and Mayor, 1991), and it contributed to the statistical evidence that a few percent of solar type stars might have brown-dwarf companions. We find that Gl~120.1C actually is an unrecognised double-lined spectroscopic pair, whose radial-velocity amplitude had been strongly underestimated by Duquennoy & Mayor (1991). It therefore does not truly belong to their sample of single-lined systems with minimum spectroscopic mass below the substellar limit. We also present the first direct detection of Gl 494B, an astrometric brown-dwarf candidate. Its luminosity does straddle the substellar limit, and it is a brown dwarf if its age is less than 300 Myr. A few more years of observations will ascertain its status from first principles.Keywords
All Related Versions
This publication has 0 references indexed in Scilit: