Some Recently-Discovered Red and Brown Dwarfs (Abstract)

Volume 34 number 2 (2006)

Frederick R. West

Abstract

(Abstract only) In a paper on recently-discovered red and brown dwarfs, Costa et al. (2005, Astron. J., 130, 337) published parallaxes obtained with the 1.5-meter telescope at Cerro Tololo Inter-American Observatory. They reported absolute parallaxes for thirty-one stars, twenty-nine of which are red dwarfs. Four of these red dwarfs are known flare stars; more of these red dwarfs may also be variable stars. A large-aperture telescope will be required to monitor these stars, since all of them are between thirteenth and nineteenth visual magnitude. The red dwarf DENIS 1048-3956 (spectral type M8.0V) is found to be only 4.00 ± 0.03 parsecs (13.06 light years) from the Sun. Teegarden’s Star (SO 0253 + 165258, spectral type M7.0V) is also discussed. Since most of the sixty-three stars now known to be closer than five parsecs (16.3 light years) are red dwarfs (45), the completeness of the present count of red dwarfs and brown dwarfs further from the Sun is discussed on the basis of these recent papers and The Catalog of nearby Stars by Gliese and Jahreiss (1991, ADC CD-ROM: Selected Astronomical Catalogs, Vol. I, Eds. Brotzmann and Gesser, NASA/ADC, GSFC, Greenbelt, MD).