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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

References

Auer, L., and Shipman, H. L.: 1976, Ap. J., submitted.Google Scholar
Bohlin, R.: 1975, Ap. J. 200, 402.Google Scholar
Cruddace, R., Paresce, F., Bowyer, S., and Lampton, M.: 1974, Ap. J. 187, 497.Google Scholar
Dupree, A. K.: 1975, Ap. J. (Letters) 200, L27.Google Scholar
Rurisen, R. H., Savedoff, M. P., and Van Horn, H. M.: 1976, Ap. J., In press.Google Scholar
Eggen, O. J., and Greenstein, J. L.: 1965, Ap. J. 141, 83.Google Scholar
Feige, J.: 1958, Ap. J. 128, 267.Google Scholar
Graham, J. A.: 1970, Contrib. Kitt Peak Natl. Obs. No. 376.Google Scholar
Greenstein, J. L., and Sargent, A. I.: 1974, Ap. J. Suppl. 28, No. 259, 157.Google Scholar
Hayakawa, S., Murakami, T., Nagase, F., Tanaka, Y., and Yamashita, K.: 1975, presented at IAU/COSPAR Symposium on Fast Transients in X- and -΃-rays, Varna, Bulgaria, May 1975; Ap. and Sp. Sei., in press.Google Scholar
Hearn, D. R., and Richardson, J. A.: 1975, IAU Circular 2890, June 17.Google Scholar
Hearn, D. R., Richardson, J. A., Bradt, H. V. D., Clark, G. W., Lewin, W. H. G., Mayer, W. F., McClintock, J. E., Primini, F. A., and Rappaport, S. A.: 1976, Ap. J. (Letters) 2013, L21.Google Scholar
Holm, A. V.: 1976, Ap. J. (Letters), submitted.Google Scholar
Humason, M. L., and Zwicky, F.: 1947, Ap. J. 105, 85.Google Scholar
Lampton, M., Margon, B., Paresce, F., Stern, R., and Bowyer, S.: 1976, Ap. J. (Letters) 203, L71.Google Scholar
Liebert, J., Margon, B., and Kuhi, L.: 1976, in preparation.Google Scholar
Luyten, W. J.: 1949, Ap. J. 109, 528.Google Scholar
Margon, B., and Bowyer, S.: 1975, Sky and Telescope 50, 4.Google Scholar
Margon, B., Lampton, M., Bowyer, S., Stern, R., and Paresce, F.: 1976c, Ap. J. (Letters), submitted.Google Scholar
Margon, B., Liebert, J., Gatewood, G., Lampton, M., Spinrad, H., and Bowyer, S.: 1976b, Ap. J., in press.Google Scholar
Margon, B., Malina, R., Bowyer, S., Cruddace, R., and Lampton, M.: 1976a, Ap. J. (Letters) 203, L25.Google Scholar
Oke, J. B.: 1974, Ap. J. Suppl. 27, No. 236, 21.Google Scholar
Rogerson, J. B., York, D. G., Drake, J. F., Jenkins, E. B., Morton, D. C, and Spitzer, L.: 1973, Ap. J. (Letters) 181, L110.Google Scholar
Shipman, H. L.: 1972, Ap. J. 177, 723.Google Scholar
Turner, H. H.: 1906, Astrographic Catalogue, Oxford Section (Oxford Observatory).Google Scholar