SPECTROSCOPY OF AN UNUSUAL EMISSION-LINE M STAR

We report moderate resolution spectroscopy of an unusual late-type, faint (I almost-equal-to 20m), emission-line star, PC 0025 + 0447. This object was discovered as part of a grism survey for high redshift quasars; the very strong (> 250 angstrom equivalent width) H-alpha emission line was detected by our automated line search algorithm. The spectrum has two unresolved emission lines (H-alpha and H-beta) near zero velocity, superposed on the absorption spectrum of a very red M dwarf which has strong K I, the strongest VO bands known, and relatively weak bands of TiO. The weakness of subordinate lines of Na I (lambda-8192) and other spectral features suggest that it is definitely a cooler, and probably fainter, analog of LHS 2924. The strength of the emission lines indicates that PC 0025 + 0447 is very young; it may be a fading, predecessor brown dwarf at an estimated M(bol) approaching 14m at a distance of almost-equal-to 60 pc.