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Soft X-ray Spectroscopy of the Hot DA White Dwarf LB1919 and the PG1159 Star PG1520+525

K. Werner·J. J. Drake·T. Rauch·S. Schuh·A. Gautschy
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Abstract

We have performed soft X-ray spectroscopy of two hot white dwarfs with the Chandra observatory using the Low Energy Transmission Grating. The first target is the hot DA white dwarf LB1919 (Teff=69000 K). This star is representative of a small group of hot DAs whose metallicities lie well below predictions from radiative levitation theory. The Chandra spectrum shows a rich absorption line spectrum which may allow to find the origin of the low-metallicity nature of these DAs. The second target is PG1520+525, a very hot non-pulsating PG1159 star. We find that it is hotter (Teff=150 000 K) than the pulsating prototype PG1159-035 (Teff=140 000) and conclude that both stars confine the blue edge of the GW Vir instability strip.

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K. Werner, J. J. Drake, T. Rauch, S. Schuh, A. Gautschy. 2006-09-30. Soft X-ray Spectroscopy of the Hot DA White Dwarf LB1919 and the PG1159 Star PG1520+525. https://arxiv.org/abs/astro-ph/0610013

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