Estimation of C II and C II* column densities along Galactic sight-lines

TL;DR

This study measures C II and C II* column densities along 14 Galactic sight-lines, revealing variations in carbon abundance and potential mechanisms influencing these differences in diverse Galactic environments.

Contribution

It provides new measurements of interstellar C II and C II* column densities across multiple Galactic sight-lines, highlighting variations in carbon abundance.

Findings

Five sight-lines show super-Solar carbon abundances.

Variations in carbon likely due to different local mechanisms.

Column densities span a wide range of hydrogen densities.

Abstract

We present interstellar C II (1334.5323 \AA) and C II* (1335.7077 \AA) column density measurements along 14 Galactic sight-lines. These sight-lines sample a variety of Galactic disk environments and include paths that range nearly two orders of magnitude in average hydrogen densities (<n(H)>) along the lines of sight. Five of the sight-lines show super-Solar gas phase abundances of carbon. Our results show that the excess carbon along these sight-lines may result from different mechanisms taking place in the regions associated with these stars.