Discovery of a Nearby Young Brown Dwarf Disk

We report the discovery of the youngest brown dwarf with a disk at 102 pc from the Sun, WISEA J120037.79 -784508.3 (W1200-7845), via the Disk Detective citizen science project. We establish that W1200-7845 is located in the 3.7(-1.4)(+4.6) Myr old epsilon Cha association. Its spectral energy distribution (SED) exhibits clear evidence of an infrared (IR) excess, indicative of the presence of a warm circumstellar disk. Modeling this warm disk, we find the data are best fit using a power-law description with a slope alpha = -0.94, which suggests that it is a young, Class II type disk. Using a single blackbody disk fit, we find T-eff,T- disk = 521 K and L-IR/L-* = 0.14. The near-IR spectrum of W1200-7845 matches a spectral type of M6.0 gamma +/- 0.5, which corresponds to a low surface gravity object, and lacks distinctive signatures of strong Pa beta or Br gamma accretion. Both our SED fitting and spectral analysis indicate that the source is cool (T-eff = 2784-2850 K), with a mass of 42-58M(Jup), well within the brown dwarf regime. The proximity of this young brown dwarf disk makes the system an ideal benchmark for investigating the formation and early evolution of brown dwarfs.