2018ApJ...853...75T

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.