Abstract:
HD 179821 (IRAS 19114+0002) is classified as a moderately metal-poor ([Fe/H] = - 0.5) post-AGB star of Teff = 5660 K and also as a very massive supergiant of Teff = 6750 K. Recent detailed studies of this star are not able to establish whether HD 179821 is a low mass star in post-AGB stage of evolution or a massive (30 Solar Mass) yellow supergiant caught in between RGB and Wolf Rayet phase (Reddy and Hrivnak (1999), Jura and Werner (1999), Thévenin et.al (2000)). Our LTE analysis of the spectrum of HD 179821 and the recent radio study of circumstellar envelope by Josselin and Lébre (2000) favours the hypothesis that it is a low mass star in post-AGB stage of evolution.
