Abundance analysis of post-AGB stars

Abstract

Using BD+46 442 as an example, we describe our analysis of the spectra of post-AGB stars (SpTs F-K, luminosity types I-II, [Fe/H]=−2.0…+0.5), obtained with the échelle spectrograph HERMES on the 1.2 m Mercator telescope. We obtain atmospheric parameters and atomic abundances using hydrogen line profiles and equivalent widths (EW) of weak metal lines. Our oscillator strengths and solar abundances for the majority of elements have been consistently adjusted to match the observed solar spectrum. The EW analysis is performed using F. Castelli's modified ATLAS9 photospheric models and C. Sneden's radiative transfer code MOOG. The resulting abundances are compared to those obtained by using the original R. Kurucz's ATLAS9 models and the WIDTH9 code. The outlined procedure can be employed for the spectroscopic analysis of the high-resolution spectra of warm (super-)giant stars in ground-based follow-up programs of Gaia.