A Multiwavelength Study of the Close Environment of HD 34078

We present 12CO(2–1) emission line observations of the region surrounding HD 34078, together with new optical and FUSE spectra of this runaway star. CO(2–1) emission peaks close to the star position and correlates well with IR thermal dust emission. Our follow‐up of CH and CH+ optical absorption lines confirms the reality of marked time variations while FUSE spectra indicate no such changes for H2. These results are consistent with a picture in which all absorption lines in HD 34078’s spectrum originate from material located close to the star, in a dense inhomogeneous shell formed at the stellar wind/ambient cloud interface where CH and CH+ are overabundant.