Different regions of line formation in the envelope of the early emission line star HD 190073.

Abstract

A description is presented of the spectral features that characterize the spectrum of HD 190073 both in the photographic region from about 3600 Å to about 6600 Å, and in the IUE ultraviolet, from about 1150 to about 3200 Å. A number of different types of profiles can be distinguished and this seems to imply that many different "broad" regions of line formation coexist in the extended envelope of the star, including regions with densities differing in several orders of magnitude. A very interesting feature in the spectrum of HD 190073 is the presence of relatively narrow emissions at 3685 Å, 3760 Å and at Hα which suggests a similarity between a compact planetary nebula - NGC 7027 - and this A star with infrared excess.