FUSE observations of hot white dwarfs

¹ Institut für Theoretische Physik und Astrophysik, Universität Kiel, 24098 Kiel, Germany e-mail: wolff, koester@astrophysik.uni-kiel.de
² Center for Astrophysical Sciences, The Johns Hopkins University, Baltimore, MD, 21218, USA e-mail: kruk@pha.jhu.edu
³ CNRS Institut d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France e-mail: allard, ferlet, alfred@iap.fr
⁴ Observatoire de Paris-Meudon, Département Atomes et Molécules en Astrophysique, 92195 Meudon Principal Cedex, France

Corresponding author: B. Wolff, wolff@astrophysik.uni-kiel.de

Received: 6 April 2001
Accepted: 26 April 2001

Abstract

We have analyzed FUSE observations of six hot white dwarf stars: four DA white dwarfs with K, the DAO Feige 55 ( K), and the DA CD -38° 10980 ( K). Photospheric lines from Si IV, P V, and S VI can be observed in the majority of the five hotter objects. Feige 55 shows also several other heavier elements. The measured abundances agree only partly with the predictions of the radiative levitation theory. We attribute this to current limitations of the models and the probable presence of mass loss. In the spectrum of CD -38° 10980, we have observed the quasi-molecular satellites of Lβ. This confirms theoretical predictions about the visibility range for these features.