Rotation curves in protoplanetary disks with thermal stratification

Abstract

In recent years the gas kinematics probed by molecular lines detected with ALMA has opened a new window to study protoplanetary disks. High spatial and spectral resolution observations have revealed the complexity of protoplanetary disk structure and correctly interpreting these data allow us to gain a better comprehension of the planet formation process. We investigate the impact of thermal stratification on the azimuthal velocity of protoplanetary disks. High resolution gas observations are showing velocity differences between CO isotopologues, which cannot be adequately explained with vertically isothermal models. The aim of this work is to determine whether a stratified model can explain this discrepancy. We analytically solve the hydrostatic equilibrium for a stratified disk and we derive the azimuthal velocity. We test the model with SPH numerical simulations and then we use it to fit for star mass, disk mass and scale radius of the sources in the MAPS sample. In particular, we use 12CO and 13CO datacubes.