SIMBAD references

2004A&A...425..997B - Astronomy and Astrophysics, volume 425, 997-1008 (2004/10-3)

New neighbours. III. 21 new companions to nearby dwarfs, discovered with adaptive optics.

BEUZIT J.-L., SEGRANSAN D., FORVEILLE T., UDRY S., DELFOSSE X., MAYOR M., PERRIER C., HAINAUT M.-C., RODDIER C., RODDIER F. and MARTIN E.L.

Abstract (from CDS):

We present some results of a CFHT adaptive optics search for companions to nearby dwarfs. We identify 21 new components in solar neighbourhood systems, of which 13 were found while surveying 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. Additionally, we resolve for the first time 6 known spectroscopic or astrometric binaries, for a total of 27 newly resolved companions. A significant fraction of the new binaries has favourable parameters for accurate mass determinations. The newly resolved companion of Gl 120.1C was thought to have a spectroscopic minimum mass in the brown-dwarf range (Duquennoy & Mayor, 1991A&A...248..485D), and it contributed to the statistical evidence that a few percent of solar-type stars might have close-in brown-dwarf companions. We find that Gl 120.1C actually is an unrecognised double-lined spectroscopic pair. Its radial-velocity amplitude had therefore been strongly underestimated by Duquennoy & Mayor (1991A&A...248..485D), and it 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 straddles the substellar limit, and it is a brown dwarf if its age is less than ∼300Myr. A few more years of observations will ascertain its mass and status from first principles.

Abstract Copyright:

Journal keyword(s): stars: binaries: general - stars: low-mass, brown dwarfs - techniques: miscellaneous

Simbad objects: 29

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