Spectroscopy of a Young Brown Dwarf in the ρ Ophiuchi Cluster

Abstract

We present observations of a young (~3-10 Myr old) brown dwarf within the ρ Ophiuchi star-forming region. A low-resolution optical spectrum exhibits a spectral type of M8.5 ± 0.5 and strong Hα emission (W_λ ~ 60 Å). After demonstrating the youth of this source through several additional lines of evidence, we place it on the H-R diagram and use the latest evolutionary tracks to derive a substellar mass of 0.01-0.06 M_☉. A more accurate mass estimate will require tests of the evolutionary tracks and temperature scales at such young ages and late types.