High resolution spectroscopy of brown dwarfs in Taurus

Detection of accretion in KPNO-Tau-3

Laboratorio de Astrofísica Espacial y Física Fundamental, INTA, PO Box 50727, 2808 Madrid, Spain e-mail: barrado@laeff.esa.es

Received: 3 February 2004
Accepted: 11 March 2004

Abstract

We present high resolution optical spectroscopy of three candidate members of the Taurus-Auriga star forming region. Based on the spectral type, the strength, profile and width of the Hα line, the detected lithium at 6708 Å, the location of these objects in the H-R diagram and the comparison with similar objects belonging to young stellar associations, we determine that they are bona fide members of the SFR with ages of ~3 Myr, and have masses at or below the substellar limit. At least in one case, there is active accretion from a circum(sub)stellar disk. This result suggests that high mass brown dwarfs go through a classical T Tauri phase and form, as stars do, from the collapse and fragmentation of a molecular cloud.