ALMA Observations of the Asymmetric Dust Disk around DM Tau

TL;DR

This paper presents high-resolution ALMA observations of DM Tau's dust disk, revealing asymmetries and potential planet-forming regions, along with modeling that suggests icy planet formation at 1 au.

Contribution

First high-resolution ALMA imaging of DM Tau's dust disk revealing asymmetries and potential planet formation zones, combined with radiative transfer modeling of the SED.

Findings

Detection of two asymmetries at 20 au possibly indicating vortices or dust peaks.

Identification of a potential inner ring at 1 au with low temperature conducive to icy planet formation.

Modeling suggests a complex disk structure with multiple rings and a central point source.

Abstract

We report an analysis of the dust disk around DM~Tau, newly observed with the Atacama Large Millimeter/submillimeter Array (ALMA) at 1.3 mm. The ALMA observations with high sensitivity (8.4~$\mu$Jy/beam) and high angular resolution (35~mas, 5.1~au) detect two asymmetries on the ring at $r\sim$20~au. They could be two vortices in early evolution, the destruction of a large scale vortex, or double continuum emission peaks with different dust sizes. We also found millimeter emissions with $\sim$50~$\mu$Jy (a lower limit dust mass of 0.3~$M_{\rm Moon}$) inside the 3-au ring. To characterize these emissions, we modeled the spectral energy distribution (SED) of DM~Tau using a Monte Carlo radiative transfer code. We found that an additional ring at $r=$ 1~au could explain both the DM~Tau SED and the central point source. The disk midplane temperature at the 1-au ring calculated in our modeling is less than the typical water sublimation temperature of 150~K, prompting the possibility of forming small icy planets there.