The physical and chemical processes in protoplanetary disks: constraints on the composition of comets

TL;DR

This review synthesizes recent observational and theoretical advances in protoplanetary disk studies, highlighting how gas and dust processes influence volatile evolution and the implications for comet composition.

Contribution

It provides a comprehensive overview of recent ALMA observations and theoretical insights into the physical and chemical processes shaping protoplanetary disks and their volatile content.

Findings

ALMA revealed grain growth and disk sub-structures.

Molecular line data constrain gas dynamics and turbulence.

Elemental abundances are inhomogeneous due to dust-gas decoupling.

Abstract

We review the recent observations of protoplanetary disks together with relevant theoretical studies with an emphasis on the evolution of volatiles. In the last several years Atacama Large Millimeter/submillimeter Array (ALMA) provided evidence of grain growth, gas-dust decoupling, and sub-structures such as rings and gaps in the dust continuum. Molecular line observations revealed radial and vertical distributions of molecular abundances and also provided significant constraints on the gas dynamics such as turbulence. While sub-millimeter and millimeter observations mainly probe the gas and dust outside the radius of several au, ice and inner warm gas are investigated at shorter wavelengths. Gas and dust dynamics are key to connecting these observational findings. One of the emerging trends is inhomogeneous distributions of elemental abundances, most probably due to dust-gas decoupling.