Homogeneous Analysis of the Dust Morphology of Transition Disks Observed with ALMA: Investigating dust trapping and the origin of the cavities

TL;DR

This study analyzes the dust morphology of 29 transition disks observed with ALMA, revealing insights into dust trapping, cavity formation, and challenging existing theories about disk evolution.

Contribution

It provides the first detailed visibility-plane analysis of a large sample of transition disks, exploring cavity origins and dust trapping mechanisms.

Findings

Cavity size is independent of stellar mass, suggesting high dust mass disks develop cavities regardless of star type.

The dust mass-stellar mass relation is flatter for transition disks than for other young stellar objects.

Photoevaporation is unlikely the main cause of cavities; giant planets or dead zones are more plausible explanations.

Abstract

We analyze the dust morphology of 29 transition disks (TDs) observed with ALMA at (sub-) millimeter-emission. We perform the analysis in the visibility plane to characterize the total flux, cavity size, and shape of the ring-like structure. First, we found that the $M_{\rm{dust}}-M_\star$ relation is much flatter for TDs than the observed trends from samples of class II sources in different star forming regions. This relation demonstrates that cavities open in high (dust) mass disks, independent of the stellar mass. The flatness of this relation contradicts the idea that TDs are a more evolved set of disks. Two potential reasons (not mutually exclusive) may explain this flat relation: the emission is optically thick or/and millimeter-sized particles are trapped in a pressure bump. Second, we discuss our results of the cavity size and ring width in the context of different physical processes for cavity formation. Photoevaporation is an unlikely leading mechanism for the origin of the cavity of any of the targets in the sample. Embedded giant planets or dead zones remain as potential explanations. Although both models predict correlations between the cavity size and the ring shape for different stellar and disk properties, we demonstrate that with the current resolution of the observations, it is difficult to obtain these correlations. Future observations with higher angular resolution observations of TDs with ALMA will help to discern between different potential origins of cavities in TDs.