Discovery of a Nearby Young Brown Dwarf Disk
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.
- Publication:
-
The Astronomical Journal
- Pub Date:
- October 2020
- DOI:
- 10.3847/1538-3881/abaccd
- arXiv:
- arXiv:2007.15735
- Bibcode:
- 2020AJ....160..156S
- Keywords:
-
- Brown dwarfs;
- Circumstellar disks;
- 185;
- 235;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Astrophysics of Galaxies