Excitation temperature of C2 and broadening of the 6196A diffuse interstellar band

TL;DR

This study reveals a correlation between the width of the 6196A diffuse interstellar band and the excitation temperature of C2 molecules, suggesting that DIB profiles are influenced by molecular excitation conditions.

Contribution

It demonstrates a direct link between DIB profile broadening and C2 excitation temperature using high-resolution spectra, a novel observational correlation.

Findings

Broader DIB profiles are associated with higher C2 excitation temperatures.

The excitation temperature was accurately derived from Phillips A-X and Mulliken D-X absorption lines.

The shape and width of the 6196A DIB depend on molecular excitation conditions.

Abstract

This paper presents a finding of the correlation between the width of a strong diffuse interstellar band at 6196A and the excitation temperature of C2 based on high resolution and high signal-to-noise ratio spectra. The excitation temperature was determined from absorption lines of the Phillips A-X and Mulliken D-X systems. The width and shape of the narrow 6196A DIB profile apparently depend on the C2 temperature, being broader for higher values.