A Disk Census for Young Brown Dwarfs

Abstract

Recent surveys have identified sub-stellar objects down to planetary masses\nin nearby star-forming regions. Reliable determination of the disk frequency in\nyoung brown dwarfs is of paramount importance to understanding their origin.\nHere we report the results of a systematic study of infrared L'-band\n(3.8-micron) disk excess in ~50 spectroscopically confirmed objects near and\nbelow the sub-stellar boundary in several young clusters. Our observations,\nusing the ESO Very Large Telescope, Keck I and the NASA Infrared Telescope\nFacility, reveal that a significant fraction of brown dwarfs harbor disks at a\nvery young age. Their inner disk lifetimes do not appear to be vastly different\nfrom those of disks around T Tauri stars. Our findings are consistent with the\nhypothesis that sub-stellar objects form via a mechanism similar to solar-mass\nstars.\n