Speaker
Description
We present high-resolution ALMA observations of the Class II brown dwarf 2MASS J04442713+2512164 (2M0444), one of the brightest and best-studied BD disks. Our 0.89 mm continuum and 12CO (3–2) line data reach a spatial resolution of 0.046 arcsec (~6.4 au), enabling the first dynamical mass measurement in the substellar regime from ALMA data. We constrain the central mass to 0.043–0.092 Msun, confirming the object as a brown dwarf, and reveal a gas-to-dust disk size ratio >6, indicating efficient radial drift. Despite the expected loss of large grains due to drift, we detect tentative evidence for substructure in the dust continuum: a gap and ring pair at ~14–16 au, consistent with the presence of a dust trap. Visibility fitting with frank and galario supports this scenario. If caused by an embedded planet, the gap would be consistent with a low-mass (0.3–7.7 M_earth) rocky planet formed via core accretion. These results challenge current models of disk evolution and planet formation in the very low-mass regime. Our study opens a new window into the early evolution of brown dwarf disks and emphasizes the importance earth of high angular resolution to characterize their architecture.
