The Spitzer c2d Survey of Nearby Dense Cores VII: Chemistry and Dynamics in L43

TL;DR

This study combines Spitzer and molecular line observations to analyze the chemical and dynamical evolution of dense cores in L43, revealing differences in molecular depletion and suggesting a longer pre-protostellar phase with rapid later-stage evolution.

Contribution

It introduces an evolutionary chemical model tailored to L43, linking molecular abundances with core evolution stages and providing insights into timescales and density changes.

Findings

CO depletion observed in both starless and protostellar sources

DCO+ lines are stronger in the starless core

Best-fit model indicates longer pre-protostellar timescale

Abstract

We present results from the Spitzer Space Telescope and molecular line observations of 9 species toward the dark cloud L43. The Spitzer images and molecular line maps suggest it has a starless core and a Class I protostar evolving in the same environment. CO depletion is seen in both sources, and DCO+ lines are stronger toward the starless core. With a goal of testing the chemical characteristics from pre- to protostellar stages, we adopt an evolutionary chemical model to calculate the molecular abundances and compare with our observations. Among the different model parameters we tested, the best-fit model suggests a longer total timescale at the pre-protostellar stage, but with faster evolution at the later steps with higher densities.