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A Physical Mechanism for the Generation of Extended Stellar Atmospheres*

Published online by Cambridge University Press:  08 February 2017

R. W. Hillendahl
R. W. Hillendahl*
Affiliation:
Department of Astronomy, University of California at Berkeley Lockheed Palo Alto Research Laboratory, 3251 Hanover Street, Palo Alto, California

Abstract

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A physical mechanism that can result in the generation of extended expanding atmospheres is discussed. The process involves the unloading of stellar material following the arrival of a shock wave at the edge of the star. The basic principles are developed from a discussion of a simplified case that has been studied in the laboratory; they are then applied to the atmosphere of a star. A radiation-hydrodynamics computation of a model cepheid is then used to obtain quantitative atmospheric profiles. The computed continuum and spectral lines during the unloading process are then examined. A discussion of the possibility that the unloading process occurs in stars other than cepheids suggests the existence of a shock visibility factor associated with ionization or dissociation in the region behind the shock front and leads to a possible alternate interpretation of the variable star instability strips in the H-R diagram.

Keywords

extended atmosphereshock wavehydrodynamiccepheids
Type
Part C
Information
International Astronomical Union Colloquium , Volume 2: Spectrum Formation in Stars With Steady-State Extended Atmospheres , August 1970 , pp. 300 - 319
Copyright
Copyright © 1970

Footnotes

†

Now at Lockheed Palo Alto Research Laboratory, 3251 Hanover Street, Palo Alto, California 93404.

(*)

This work was made possible by a grant of computer time made available by the Berkeley Astronomy Department and by a Lockheed Independent Research Grant.

References

1. Weymann, R., Astrophys. J., 136, 476 (1962).Google Scholar
2. Hillendahl, R. W., Dissertation, Univ. of California at Berkeley (1968).Google Scholar
3. Zeldovich, Ya. B. and Raizer, Yu. P., Physics of Shock Waves and High-Temperature. Hydrodynamic Phenomena, Academic Press, New York and London (1966), pp. 101, 716, 762.Google Scholar
4. Bird, G. A., Astrophys. J., 139, 675 (1964).Google Scholar
5. Sakurai, A., J. fluid Mech., 1, 436 (1956).Google Scholar
6. Arp, H. C., Astronomical J., 60, 1 (1955).Google Scholar
7. Abt, H. A., Astrophys. J., 126, 138 (1957).CrossRefGoogle Scholar
8. Moreton, G. E., Sky and Telescope, 21, 145 (1961).Google Scholar
9. Hillendahl, R. W., “Approximation Techniques for Radiation-Hydrodynamics Computations,” Defense Atomic Support Agency Report 1522 (1964).Google Scholar
10. Hillendahl, R. W., Proceedings of the Workshop on the Interdisciplinary Aspects of Radiative Transfer, ed. R. Goulard Joint Institute for Laboratory Astrophysics, Boulder, Colorado (1965).Google Scholar
11. Henyey, L. G., LeLevier, R., Levee, R. D., Bohm, K. H., and Willets, L., Astrophys. J., 129, 628 (1959).CrossRefGoogle Scholar
12. Christy, R. H., California Institute of Technology, private communication (1968).Google Scholar
13. Oke, J. B., Astrophys. J., 133, 90 (1961).Google Scholar
14. Stebbins, J., Kron, G. F., and Smith, J. L., Astrophys. J., 115, 292 (1952).Google Scholar
15. Whitney, C., Dissertation, Harvard University (1955).Google Scholar
16. Underhill, Anne B., Astrophys. J., 106, 128 (1948).CrossRefGoogle Scholar
17. Aller, L. H., Astrophys, Ronald Press, New York (1953).Google Scholar
18. Rybicki, G. B., “Routine for Evaluation of the Voigt Function,” forwarded by D. G. Hummer.Google Scholar
19. Edmonds, F. N. Jr., Schluter, F. M., and Wells, D. C. III, Memoirs, Roy, St. Soc. 71, 271 (1967).Google Scholar
20. Van Hoof, A. and Deurinck, R., Astrophys. J., 115, 166 (1952).Google Scholar
21. Kraft, R. P., Camp, D. C., Fernie, J. D., Fujita, C., and Hughes, W. T., Astrophys. J., 129, 50 (1959).CrossRefGoogle Scholar
22. Jacobsen, T. S., Pub. Dominion Ast. Obs. X, No. 6, 145 (1956).Google Scholar
23. Kraft, R. P., in Stellar Atmospheres, ed. Greenstein, J., Univ. of Chicago Press (1960).Google Scholar
24. Bernheimer, W. E., Lund Medd., Ser. II, 61, 11 (1930).Google Scholar
25. Preston, G. W., Astrophys. J., 134, 633 (1961).CrossRefGoogle Scholar
26. Allen, C. W., Astrophysical Quantities, Univ. of London, Athlone Press (1963), pp. 201, 208.Google Scholar