2025ApJ...986L..11S -
Astrophys. J., 986, L11 (2025/June-2)
Hints of Disk Substructure in the First Brown Dwarf with a Dynamical Mass Constraint.
SANTAMARIA-MIRANDA A., CURONE P., PEREZ L., KURTOVIC N.T., AGURTO-GANGAS C., SIERRA A., DE GREGORIO-MONSALVO I., HUELAMO N., MILEY J.M., PALAU A., PINILLA P., REBOLLIDO I., RIBAS A., RIVIERE-MARICHALAR P., SCHREIBER M.R., SAI J. and CARRERA B.
Abstract (from CDS):
We present high-resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations at 0.89 mm of the Class II brown dwarf 2MASS J04442713+2512164 (2M0444), achieving a spatial resolution of 0$\mathop{.}\limits^{^{\prime\prime} }$046 (∼6.4 au at the distance to the source). These observations targeted continuum emission together with 12CO (3-2) molecular line. The line emission traces a Keplerian disk, allowing us to derive a dynamical mass between 0.043 and 0.092 M⊙ for the central object. We constrain the gas-to-dust disk size ratio to be ∼7, consistent with efficient radial drift. However, the observed dust emission suggests that a dust trap is present, enough to retain some dust particles. We perform visibility fitting of the continuum emission, and under the assumption of annular substructure, our best fit shows a gap and a ring at 98.1${}_{-8.4}^{+4.2}$ mas (∼14 au) and 116.0${}_{-4.8}^{+4.2}$ mas (∼16 au), respectively, with a gap width of 20 mas (∼3 au). To ensure robustness, the data were analyzed through a variety of methods in both the image and uv planes, employing multiple codes and approaches. This tentative disk structure could be linked to a possible planetary companion in the process of formation. These results provide the first dynamical mass of the lowest mass object to date, together with the possible direct detection of a substructure, offering new insights into disk dynamics and planet formation in the very low-mass regime. Future higher spatial resolution ALMA observations will be essential to confirm these findings and further investigate the link between substructures and planet formation in brown dwarf disks.
Abstract Copyright:
© 2025. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Brown dwarfs - Circumstellar dust - Millimeter astronomy - Planet formation - Protoplanetary disks - Radio interferometry - Submillimeter astronomy
Simbad objects:
6
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