An Asymmetric Dust Ring around a Very Low Mass Star ZZ Tau IRS

We present Atacama Large Millimeter/submillimeter Array (ALMA) gas and dust observations at band 7 (339 GHz: 0.89 mm) of the protoplanetary disk around a very low mass star ZZ Tau IRS with a spatial resolution of 0.'' 25. The (CO)-C-12 J = 3 -> 2 position-velocity diagram suggests a dynamical mass of ZZ Tau IRS of similar to 0.1-0.3 M circle dot(;). The disk has a total flux density of 273.9 mJy, corresponding to an estimated mass of 24-50 M-circle plus in dust. The dust emission map shows a ring at r = 58 au and an azimuthal asymmetry at r = 45 au with a position angle of 135 degrees. The properties of the asymmetry, including radial width, aspect ratio, contrast, and contribution to the total flux, were found to be similar to the asymmetries around intermediate mass stars (similar to 2 M-circle dot;) such as MWC 758 and IRS 48. This implies that the asymmetry in the ZZ Tau IRS disk shares a similar origin with others, despite the star being similar to 10 times less massive. Our observations also suggest that the inner and outer parts of the disk may be misaligned. Overall, the ZZ Tau IRS disk shows evidence of giant planet formation on a similar to 10 au scale at a few megayears. If confirmed, it will challenge existing core accretion models in which such planets have been predicted to be extremely hard to form around very low mass stars.

Automated summary

This study presents gas and dust observations of the protoplanetary disk around ZZ Tau IRS using ALMA. The observations reveal asymmetries and suggest the potential formation of planets in the disk.