Discovery of a Brown Dwarf with Quasi-spherical Mass Loss
Dunham, Michael M.; Jofré, Paula; Cieza, Lucas A.; Williams, Jonathan P.; Casassus, Simon; Zurlo, Alice; Humphreys, Elizabeth; González-Ruilova, Camilo; Nogueira, Pedro H.; Hales, Antonio; Ruíz-Rodríguez, Dary A.; Almendros-Abad, Victor; Muzic, Koraljka; Peña Ramirez, Karla; Batalla-Falcon, Grace; Paladini, Claudia; Tobin, John
United States, Chile, Portugal
Abstract
We report the serendipitous discovery of an elliptical shell of CO associated with the faint stellar object SSTc2d J163134.1-240060 as part of the "Ophiuchus Disk Survey Employing ALMA" (ODISEA), a project aiming to study the entire population of protoplanetary disks in the Ophiuchus Molecular Cloud from 230 GHz continuum emission and 12CO (J = 2-1), 13CO (J = 2-1) and C18CO (J = 2-1) lines readable in Band 6. Remarkably, we detect a bright 12CO elliptical shape emission of ~3″ × 4″ toward SSTc2d J163134.1-240060 without a 230 GHz continuum detection. Based on the observed near-IR spectrum taken with the Very Large Telescope (KMOS), the brightness of the source, its three-dimensional motion, and Galactic dynamic arguments, we conclude that the source is not a giant star in the distant background (>5-10 kpc) and is most likely to be a young brown dwarf in the Ophiuchus cloud, at a distance of just ~139 pc. This is the first report of quasi-spherical mass loss in a young brown dwarf. We suggest that the observed shell could be associated with a thermal pulse produced by the fusion of deuterium, which is not yet well understood, but for a substellar object is expected to occur during a short period of time at an age of a few Myr, in agreement with the ages of the objects in the region. Other more exotic scenarios, such as a merger with planetary companions, cannot be ruled out from the current observations.