Differences in the Gas and Dust Distribution in the Transitional Disk of a Sun-like Young Star, PDS 70

Abstract

We present ALMA 0.87 mm continuum, HCO+ J = 4-3 emission line, and CO J = 3-2 emission line data of the disk of material around the young, Sun-like star PDS 70. These data reveal the existence of a possible two-component transitional disk system with a radial dust gap of 0.'' 42 +/- 0.'' 05, an azimuthal gap in the HCO+ J = 4-3 moment zero map, as well as two bridge-like features in the gas data. Interestingly these features in the gas disk have no analog in the dust disk making them of particular interest. We modeled the dust disk using the Monte Carlo radiative transfer code HOCHUNK3D using a two-disk component. We find that there is a radial gap that extends from 15 to 60 au in all grain sizes, which differs from previous work.