2016ApJ...822L...1S

We present WISEA J114724.10-204021.3, a young, low-mass, high-probability member of the TW Hya association (TWA). WISEA J114724.10-204021.3 was discovered based on its red AllWISE color (W1 - W2 = 0.63 mag) and extremely red 2MASS J - K S color (>2.64 mag), the latter of which is confirmed with near-infrared photometry from the Visible and Infrared Survey Telescope for Astronomy Hemisphere Survey (J - K S = 2.57 ± 0.03). Follow-up near-infrared spectroscopy shows a spectral type of L7 ± 1 as well as several spectroscopic indicators of youth. These include a peaked H-band shape and a steeper K-band slope, traits typically attributed to low surface gravity. The sky position, proper motion, and distance estimates of WISEA J114724.10-204021.3 are all consistent with membership in the ∼10 Myr old TWA. Using the age of the TWA and evolutionary models, we estimate the mass of WISEA J114724.10-204021.3 to be 5-13 M Jup, making it one of the youngest and lowest-mass free-floating objects yet discovered in the Solar neighborhood.