Discovery of a Brown Dwarf with Quasi-spherical Mass Loss

• Published in: The Astrophysical journal Vol. 938; no. 1; pp. 54 - 73
• Main Authors: Ruíz-Rodríguez, Dary A., Cieza, Lucas A., Casassus, Simon, Almendros-Abad, Victor, Jofré, Paula, Muzic, Koraljka, Ramirez, Karla Peña, Batalla-Falcon, Grace, Dunham, Michael M., González-Ruilova, Camilo, Hales, Antonio, Humphreys, Elizabeth, Nogueira, Pedro H., Paladini, Claudia, Tobin, John, Williams, Jonathan P., Zurlo, Alice
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01-10-2022; IOP Publishing
• Subjects: Astrophysics; Brown dwarf stars; Circumstellar clouds; Continuum radiation; Deuterium; Emissions; Giant stars; Molecular clouds; Near infrared radiation; Planet formation; Protoplanetary disks; Space telescopes; Stellar wind bubbles; Stellar winds; Three dimensional motion; Very Large Telescope
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ac8ff5

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
12
CO (
J
= 2–1),
13
CO (
J
= 2–1) and C
18
CO (
J
= 2–1) lines readable in Band 6. Remarkably, we detect a bright
12
CO 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.