Discovery of a Nearby Young Brown Dwarf Disk
Debes, John H.; Kiman, Rocio; Schneider, Adam C.; Faherty, Jacqueline K.; Kuchner, Marc J.; Gagné, Jonathan; Wisniewski, John P.; Bardalez Gagliuffi, Daniella C.; Meisner, Aaron; Durantini Luca, Hugo A.; Hyogo, Michiharu; Silverberg, Steven M.; Bans, Alissa S.; Bosch, Milton K. D.; Disk Detective Collaboration; Schutte, Maria C.; Lawson, Kellen D.; Kovacevic, Natalie; Holden, Jonathan
United States, Canada, Argentina, Japan
Abstract
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 ɛ 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 α = -0.94, which suggests that it is a young, Class II type disk. Using a single blackbody disk fit, we find ${T}_{\mathrm{eff},\mathrm{disk}}=521\,K$ and ${L}_{\mathrm{IR}}/{L}_{* }=0.14$ . The near-IR spectrum of W1200-7845 matches a spectral type of M6.0 $\gamma \,\pm $ 0.5, which corresponds to a low surface gravity object, and lacks distinctive signatures of strong Paβ or Brγ accretion. Both our SED fitting and spectral analysis indicate that the source is cool (Teff = 2784-2850 K), with a mass of 42-58 MJup, 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.