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Preprint 09l/10

Discovery of Iron in PG1159 Stars

Klaus Werner (1), Thomas Rauch (1) and Jeffrey W. Kruk (2)

1) Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics,
Eberhard Karls University, D-72076 Tübingen, Germany
2) NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA

To be published in: Proceedings of the 17th European White Dwarf Workshop, AIP Conference Series

Abstract. The lack of Fe VII lines in PG1159 stars had led to the conclusion that in some objects iron must be strongly depleted.We have now detected Fe X lines in FUSE spectra of the very hottest PG1159 stars (T_eff = 150 000 - 200 000K; RXJ2117.1+3412,K1-16, NGC246, Longmore 4). Surprisingly, we derive a solar iron abundance. It is conspicuous that they are among the most massive PG1159 stars (0.71 - 0.82 M_sun), in contrast to those objects for which strongest Fe-deficiency was claimed (0.53 - 0.56 M_sun). Based on new Fe VIII line identifications in SOHO/SUMER UV spectra of the Sun, we were able to detect these lines in FUSE spectra of several "cooler" (T_eff <~ 150 000) objects, among them is the prototype PG1159−035. An abundance analysis is in progress.
 

Preprint (125 kb PDF file including figures)

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