A Young Planetary-Mass Object in the ρ Oph Cloud Core

February 2010 • 2010ApJ...709L.158M

Authors • Marsh, Kenneth A. • Kirkpatrick, J. Davy • Plavchan, Peter

Abstract • We report the discovery of a young planetary-mass brown dwarf in the ρ Oph cloud core. The object was identified as such with the aid of a 1.5-2.4 μm low-resolution spectrum obtained using the NIRC instrument on the Keck I telescope. Based on the COND model, the observed spectrum is consistent with a reddened (A_V ~ 15-16) brown dwarf whose effective temperature is in the range 1200-1800 K. For an assumed age of 1 Myr, comparison with isochrones further constrains the temperature to ~1400 K and suggests a mass of ~2-3 Jupiter masses. The inferred temperature is suggestive of an early T spectral type, which is supported by spectral morphology consistent with weak methane absorption. Based on its inferred distance (~100 pc) and the presence of overlying visual absorption, it is very likely to be a ρ Oph cluster member. In addition, given the estimated spectral type, it may be the youngest and least massive T dwarf found so far. Its existence suggests that the initial mass function for the ρ Oph star-forming region extends well into the planetary-mass regime.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2010ApJ...709L.158M
• PDF https://stacks.iop.org/2041-8205/709/L158/pdf
• PREPRINT http://arxiv.org/abs/0912.3774
• DATA https://irsa.ipac.caltech.edu/bibdata/2010/M/2010ApJ...709L.158M.html
• ELECTR https://doi.org/10.1088%2F2041-8205%2F709%2F2%2FL158