CO abundances in a protostellar cloud: freeze-out and desorption in the envelope and outflow of L483

TL;DR

This study models CO isotope emissions in the protostellar cloud L483 to understand how physical conditions like freeze-out and outflows affect molecular abundances and line profiles.

Contribution

It introduces a 3D molecular line transport model that simulates CO isotopomer emissions considering freeze-out, density, and infall in a protostellar environment.

Findings

Models replicate JCMT observations accurately.

Linewidths vary with outflow activity and density.

CO isotopomers trace different physical components.

Abstract

CO isotopes are able to probe the different components in protostellar clouds. These components, core, envelope and outflow have distinct physical conditions and sometimes more than one component contributes to the observed line profile. In this study we determine how CO isotope abundances are altered by the physical conditions in the different components. We use a 3D molecular line transport code to simulate the emission of four CO isotopomers, 12CO J=2-1, 13CO J=2-1, C18O J=2-1 and C17O J=2-1 from the Class 0/1 object L483, which contains a cold quiescent core, an infalling envelope and a clear outflow. Our models replicate JCMT (James Clerk Maxwell Telescope) line observations with the inclusion of freeze-out, a density profile and infall. Our model profiles of 12CO and 13CO have a large linewidth due to a high velocity jet. These profiles replicate the process of more abundant material being susceptible to a jet. C18O and C17O do not display such a large linewidth as they trace denser quiescent material deep in the cloud.