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Cyclotron Absorption in GD229?

Published online by Cambridge University Press:  25 April 2016

D. T. Wickramasinghe
Affiliation:
Department of Applied Mathematics, Australian National University
Brian Martin
Affiliation:
Department of Applied Mathematics, Australian National University

Extract

The existence of a group of magnetic white dwarfs with mean surface fields of between ~5 × 106 G and ~2 × 1O7 G is now firmly established through the discovery of Zeeman structure in hydrogen and helium lines (Angel et al. 1974, Liebert et al. 1975, Wickramasinghe et al. 1977, Martin & Wickramasinghe 1978, Liebert et al. 1977). There is considerable evidence from polarimetric studies for even higher fields in some white dwarfs (Angel 1977). Most of these stars are cool and show nearly continuous spectra or weak unidentified absorption features. The possibility of cyclotron absorption in white dwarfs was first discussed in connection with the infrared polarisation spectrum of one of these stars, Grw + 70°8247 (Kemp 1970). More recently the polarised white dwarf GD229 was found to have a rich optical spectrum with a strong feature at λ4185, for which cyclotron absorption has been mentioned as a possible origin (Angel 1977, Greenstein & Boksenberg 1977), though without supporting computations. In this letter we use models to investigate this possibility further.

Type
Galactic
Copyright
Copyright © Astronomical Society of Australia 1978

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References

Angel, J. R. P., Astrophys. J., 216, 1 (1977).Google Scholar
Angel, J. R. P., Annual Reviews of Astronomy and Astrophysics, 16 (1978).Google Scholar
Angel, J. R. P., Carswell, R., Strittmatter, P. A., Beaver, E. A., & Harms, R., Astrophys. J., 194, L47 (1974).Google Scholar
Giclas, H. L., Burnham, R. & Thomas, N. O. R., Lowell Observatory Bulletin No. 125 (1965).Google Scholar
Greenstein, J. L. & Boksenberg, G., Preprint (1977).Google Scholar
Greenstein, J. L., Schmidt, M. & Searle, L., Astrophys. J., 190, L27 (1974).Google Scholar
Kemic, S. B., Joint Institute Laboratory Astrophysics Rep. 113 (1974).Google Scholar
Kemp, J. C, Astrophys. J., 162, L69 (1970).Google Scholar
Lamb, F. K., & Sutherland, P. G., Physics of dense matter, p. 265, ed. Hansen, C. J., D. Reidel, Dordrecht, Holland (1974).Google Scholar
Landstreet, J. D. & Angel, J. R, P., Astrophys. J., 190. L25 (1974).Google Scholar
Liebert, J., Pub. A. S. P.,88, 490 (1976).Google Scholar
Liebert, J., Angel, J. R. P. & Landstreet, J. D., Astrophys. J., 202, L139 (1975).Google Scholar
Liebert, J., Angel, J. R. P., Stockman, H. S., Spinrad, H. & Beaver, E. A., Astrophys. J., 214, 457 (1977).Google Scholar
Martin, .’B. & Wickramasinghe, D. T., Mon. Not. R. Astron. Soc, 183 (1978).Google Scholar
Praddaude, H. C., Phys. Rev. A, 6, 1321 (1972).Google Scholar
Smith, E. R., Henry, R. J. W., Surmelian, G. L., O’Connell, R. F. & Rajagopal, A. K., Phys. Rev. D, 6, 3700(1972).Google Scholar
Swedlund, J. B., Wolstencroft, R. D., Michalsky, J. J. & Kemp, J. C, Astrophys. J., 187. L121 (1974).CrossRefGoogle Scholar
Unno, W., Pubi. Astr. Soc. Japan.S, 108 (1956).Google Scholar
Wickramasinghe, D. T., Mem. R. Astr. Soc, 76, 129 (1972).Google Scholar
Wickramasinghe, D. T., Whelan, J.A: Bessell, J.&M. S., Mon. Not. R. Astr. Soc, 180, 373 (1977).Google Scholar