Survival of interstellar molecules to prestellar dense core collapse and early phases of disk formation

TL;DR

This study uses advanced 3D chemical simulations to investigate how interstellar molecules survive the collapse into prestellar cores and early disk formation, revealing that chemical content is largely conserved during this process.

Contribution

It introduces a novel integration of the Nautilus chemical model with RAMSES MHD simulations to analyze chemical evolution during early disk formation.

Findings

Chemical content is conserved during collapse from cloud to disk.

Comets may contain molecules directly inherited from interstellar medium.

Complex molecules likely form in disks due to higher densities and temperatures.

Abstract

An outstanding question of astrobiology is the link between the chemical composition of planets, comets, and other solar system bodies and the molecules formed in the interstellar medium. Understanding the chemical and physical evolution of the matter leading to the formation of protoplanetary disks is an important step for this. We provide some new clues to this long-standing problem using three-dimensional chemical simulations of the early phases of disk formation: we interfaced the full gas-grain chemical model Nautilus with the radiation-magnetohydrodynamic model RAMSES, for different configurations and intensities of magnetic field. Our results show that the chemical content (gas and ices) is globally conserved during the collapsing process, from the parent molecular cloud to the young disk surrounding the first Larson core. A qualitative comparison with cometary composition suggests that comets are constituted of different phases, some molecules being direct tracers of interstellar chemistry, while others, including complex molecules, seem to have been formed in disks, where higher densities and temperatures allow for an active grain surface chemistry. The latter phase, and its connection with the formation of the first Larson core, remains to be modeled.