The composition of the protosolar disk and the formation conditions for comets

TL;DR

This paper reviews how the composition of cometary volatiles and protostellar disks reveal the physical and chemical conditions during the formation of the solar system, integrating observational and theoretical insights.

Contribution

It synthesizes recent research on cometary volatiles and protostellar disks to better understand the formation conditions of comets and the early solar nebula.

Findings

Cometary compositions reflect processing from molecular cloud to solar nebula.

Protostellar disks provide insights into early solar system conditions.

Understanding disk evolution helps explain comet diversity.

Abstract

Conditions in the protosolar nebula have left their mark in the composition of cometary volatiles, thought to be some of the most pristine material in the solar system. Cometary compositions represent the end point of processing that began in the parent molecular cloud core and continued through the collapse of that core to form the protosun and the solar nebula, and finally during the evolution of the solar nebula itself as the cometary bodies were accreting. Disentangling the effects of the various epochs on the final composition of a comet is complicated. But comets are not the only source of information about the solar nebula. Protostellar disks around young stars similar to the protosun provide a way of investigating the evolution of disks similar to the solar nebula while they are in the process of evolving to form their own solar systems. In this way we can learn about the physical and chemical conditions under which comets formed, and about the types of dynamical processing that shaped the solar system we see today. This paper summarizes some recent contributions to our understanding of both cometary volatiles and the composition, structure and evolution of protostellar disks.