Relation between CH cation and neutral/molecular hydrogen

Abstract

Observations of interstellar absorption bands of CH molecule at 3957 and 4232 Å were applied to determine column densities toward 53 stars. The targets were selected because the atomic and molecular hydrogen column densities are published. The data on CH were acquired using four echelle spectrographs situated in both the Northern and Southern hemispheres. Spatial relations between column densities of CH and those of molecular, atomic and total hydrogen show large scatter, suggesting there is no relation between abundances of methylidyne cation and hydrogen in any form. © 2008 ESO.