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 \substack { +4.6 \ -1.4 } Myr-old \varepsilon 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 it is a young , Class II type disk .
Using a single blackbody disk fit , we find T _ { eff,disk } = 521 K and L _ { IR } / L _ { * } = 0.14 .
The near-infrared 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 Pa \beta or Br \gamma accretion .
Both our SED fitting and spectral analysis indicate the source is cool ( T _ { eff } = 2784–2850 K ) , with a mass of 42–58 M _ { 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 .