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Extreme Ultraviolet Observations of White Dwarfs

Published online by Cambridge University Press:  30 March 2016

Michael Lampton
Affiliation:
Space Sciences Laboratory, University of California, Berkeley
Bruce Margon
Affiliation:
Space Sciences Laboratory, University of California, Berkeley
Stuart Bowyer
Affiliation:
Space Sciences Laboratory, University of California, Berkeley

Extract

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Observations shortward of the hydrogen Lyman limit provide sensitive determinations of stellar temperatures and interstellar absorption. Such data are of particular value in studies of hot white dwarfs, for which a large fraction of the emission occurs in the extreme ultraviolet band (100-1000 Å). Observations of HZ 43 and Feige 24 have been obtained with the Apollo-Soyuz extreme ultraviolet telescope; both stars are copious EUV emitters, with 4 × 10−9 and 3 × 10−9 erg/cm2 sec in the 170-620 A band respectively. The EUV data combined with optical spectrophotometry, allow their temperatures to be estimated as 80, 000 and 60, 000 K respectively. The corresponding interstellar neutral hydrogen column densities are ~ 4 × 1018 cm−2.

Type
Joint Dicussions
Copyright
Copyright © Reidel 1977

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