SIMBAD references

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.