2MASS J11151597+1937266: A Young, Dusty, Isolated, Planetary-mass Object with a Potential Wide Stellar Companion

January 2018 • 2018ApJ...853...75T

Authors • Theissen, Christopher A. • Burgasser, Adam J. • Bardalez Gagliuffi, Daniella C. • Hardegree-Ullman, Kevin K. • Gagné, Jonathan • Schmidt, Sarah J. • West, Andrew A.

Abstract • We present 2MASS J11151597+1937266, a recently identified low-surface-gravity L dwarf, classified as an L2γ based on Sloan Digital Sky Survey optical spectroscopy. We confirm this spectral type with near-infrared spectroscopy, which provides further evidence that 2MASS J11151597+1937266 is a low-surface-gravity L dwarf. This object also shows significant excess mid-infrared flux, indicative of circumstellar material; and its strong Hα emission (EW_Hα = 560 ± 82 Å) is an indicator of enhanced magnetic activity or weak accretion. Comparison of its spectral energy distribution to model photospheres yields an effective temperature of {1724}_-38⁺¹⁸⁴ {{K}}. We also provide a revised distance estimate of 37 ± 6 pc using a spectral type-luminosity relationship for low-surface-gravity objects. The three-dimensional galactic velocities and positions of 2MASS J11151597+1937266 do not match any known young association or moving group. Assuming a probable age in the range of 5-45 Myr, the model-dependent estimated mass of this object is between 7 and 21 M _Jup, making it a potentially isolated planetary-mass object. We also identify a candidate co-moving, young stellar companion, 2MASS J11131089+2110086.

Links

• PREPRINT http://arxiv.org/abs/1712.03964
• ELECTR https://doi.org/10.3847/1538-4357/aaa0cf
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2018ApJ...853...75T
• PDF https://iopscience.iop.org/article/10.3847/1538-4357/aaa0cf/pdf
• DATA https://irsa.ipac.caltech.edu/bibdata/2018/T/2018ApJ...853...75T.html