HD 111786: a spectroscopic binary λ Boo star.

Abstract

HD 111786 = HR 4881 is one of the most interesting λ Boo stars; in fact it is one of the few stars of this class which shows narrow features that can be interpreted as remnants of the circumstellar matter from which star was formed. On the basis of optical observations and inspection of IUE spectra, we demonstrate that HD 111786 is, as a matter of fact, a binary system and that one of the component is characterized by a narrow line spectrum; the main contribution to the narrow absorptions is not that of circumstellar gas related to the λ Boo phenomenon, but is due to the photosphere of the companion star.