Iron abundance in the prototype PG 1159 star, GW Vir pulsator PG 1159 − 035, and related objects^⋆

K. Werner¹, T. Rauch¹, J. W. Kruk² and R. L. Kurucz³

¹ Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls Universität Tübingen, Sand 1, 72076 Tübingen, Germany
e-mail: werner@astro.uni-tuebingen.de
² NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
³ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

Received: 31 March 2011
Accepted: 3 May 2011

Abstract

We performed an iron abundance determination of the hot, hydrogen deficient post-AGB star PG 1159 − 035, which is the prototype of the PG 1159 spectral class and the GW Vir pulsators, and of two related objects (PG 1520 + 525, PG 1144 + 005), based on the first detection of Fe viii lines in stellar photospheres. In another PG 1159 star, PG 1424 + 535, we detect Fe vii lines. In all four stars, each within T_eff = 110 000−150 000 K, we find a solar iron abundance. This result agrees with our recent abundance analysis of the hottest PG 1159 stars (T_eff = 150 000−200 000 K) that exhibit Fe x lines. On the whole, we find that the PG 1159 stars are not significantly iron deficient, in contrast to previous notions.