The evolutionary status of the bright high-latitude supergiant HD190390

Abstract

Despite its mean apparent magnitude of m(v)=6.39, the evolutionary status of HD190390 (HR7671), a luminous F-type supergiant at high galactic latitude, is still not very clear, but in most papers a post-AGB classification is assumed. New observational material has been obtained with four different instruments and is presented here. An extensive abundance analysis based on high resolution, high signal-to-noise NTT+EMMI spectra confirms the metal deficiency of this object ([Fe/H]=-1.6), together with a high lithium content (log(Li)=1.9). A variability analysis based on Geneva photometry over seven years reveals beating with a period of +/-3000 days. It is, however, not clear whether this beating is caused by a stable triplet, or it is the consequence of small changes in the main frequency. More recent data obtained with the HIPPARCOS satellite and the Mercator telescope not only confirm the main period, but also support the presence of a second periodicity of 11 days, which was also found in the Geneva photometry. A conclusive evolutionary status of this object is not given, but alternative to the UU Her (i.e. post-AGB) status, a W Vir classification is discussed.