The Unique Spectrum of the Brown Dwarf Candidate GD 165B and Comparison to the Spectra of Other Low-Luminosity Objects

The paper compares the 6300-9000-A spectrum of GD 165 B to spectra of three of the lowest-luminosity red objects known: LHS 2924, LHS 2065, and PC 0025+0447. A temperature for this object is estimated using extrapolations to absolute magnitude vs temperature for low-mass stars. Two estimates are given for the location of GD 165 B on the H-R diagram. Neither data point yields an unambiguous classification as either star or brown dwarf for this object. It is concluded that GD 165 B has redder colors and fainter absolute magnitudes than any known main sequence star, with a spectrum unlike that of any known M dwarf.