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 r Ophiuchi star-forming region. A low-resolution optical spectrum exhibits a spectral type of M8.5  0.5 and strong Ha emission (Wl 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 ∼ 60 A ˚ ). mass estimate will require tests of the evolutionary tracks and temperature scales at such young ages and late types. ,