Atmospheric Abundances in Post-AGB candidates of Intermediate Temperature

Abstract

Detailed atmospheric abundances have been calculated for a sample of A-G supergiant stars with IR fluxes and/or high galactic latitudes. HD 172481 and HD 158616 show clear indications of being post-AGB stars that have experienced third dredge-up. HD 158616 is carbon-rich while the abundance pattern of HD 172481 and its large Li enhancement gives support to the hot bottom burning scenario that explains paucity of carbon-rich stars among AGB stars. HD 172324 is very likely a hot post-AGB star that shows a strong carbon deficiency. HD 725, HD 218753 and HD 331319 also appear to be evolved objects between the red giant and the AGB. HD 9167, HD 173638 with a few exceptions, reflect solar abundances and no signs of post red giant evolution. They are most likely young massive disk supergiants. Further analysis of proto-Planetary Nebula HDE 341617 reveals that He lines show signs of velocity stratification. The emission lines have weakened considerably since 1993. The envelope expands at 19 km s${}^{-1}$ relative to the star. Atmospheric abundances, evolutionary tracks and isochrones are used to estimate masses and ages of all stars in the sample.

19 pages (text), 14 tables, 5 figures

References in corpus (1)

• HD172481: a super lithium-rich metal-deficient post-AGB binary with a red AGB companion

Cited by in corpus (17)

• Galactic chemical evolution of Lithium: interplay between stellar sources"
• A search for diffuse bands in the circumstellar envelopes of post-AGB stars
• Luminosities and masses of single Galactic Post-Asymptotic Giant Branch (Post-AGB) stars with distances from $Gaia$ EDR3: The revelation of an $s$-process diversity
• Where Are the Binaries? Results of a Long-Term Search for Radial Velocity Binaries in Proto-Planetary Nebulae
• The dust envelope of the pre-planetary nebula IRAS19475+3119
• Post-AGB stars as testbeds of nucleosynthesis in AGB stars
• V2324Cyg - an F-type star with fast wind
• Variability in Proto-Planetary Nebulae: IV. Light Curve Analyses of Four Oxygen-Rich, F Spectral-Type Objects
• HD172189: another step in furnishing one of the best laboratories known for asteroseismic studies
• Chemical composition of evolved stars of high galactic latitude
• Chemical composition of A--F type post-AGB candidates
• Photometric and Spectroscopic Study of the Supergiant with an Infrared Excess V1027 Cygni
• s-process Enriched Post-AGB Star J003643.94-723722.1 in the SMC with an Extreme C/O Ratio and the First Precise Detection of Lead
• A non-LTE abundance analysis of the post-AGB star ROA 5701
• On the evolutionary status of high-latitude variable V534 Lyr
• Spectroscopy of supergiants with infrared excess: results of 1998-2018
• High-resolution optical spectroscopy of the post-AGB supergiant V340 Ser (=IRAS 17279$-$1119)