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The Effects of Chromospheric Radiation on the Circumstellar Chemistry of Evolved Stars

Published online by Cambridge University Press:  04 August 2017

A. E. Glassgold
A. E. Glassgold*
Affiliation:
New York University, New York, NY 10003 USA

Abstract

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The physical and chemical properties of the circumstellar envelopes of evolved stars are strongly affected by the interstellar radiation field. Other sources of UV radiation should be similarly effective, and some examples are nearby stars (including companions), chromospheres, and the central stars of planetary nebulae. We consider the particular case of Alpha Ori, which has a chromosphere and an extended CSE with a small dust to gas ratio. Its properties are dominated by the chromospheric and interstellar radiation fields. The most common species are neutral atoms and first ions, and the electron fraction is high throughout the entire CSE, i.e. at least 10−4. The abundances of neutrals peak in the outer CSE close to where the chromospheric and interstellar radiation fields are equal. An important application is KI, whose density has been measured by scattering. The theory predicts that the slope of the KI density should change from about −1.5 to −3.5 in the outer envelope, the exact values being determined by the temperature distribution. The mass loss rate implied by the KI density is of the order of 4×10−6 M⊙ yr−1.

Type
Circumstellar Shells
Information
Symposium - International Astronomical Union , Volume 120: Astrochemistry , 1987 , pp. 379 - 385
Copyright
Copyright © Reidel 1987 

References

Bernat, A.P. 1976, , University of Texas, Austin.Google Scholar
Bernat, A.P., Hall, D.N.B., Hinkle, K.H., and Ridgway, S. 1979, Ap. J. (Letters) 233, L135.Google Scholar
Clegg, R.E.S., van Ijzendoorn, L.J., and Allamendola, L.J. 1983, M.N. 203, 125.Google Scholar
Forrest, W.J., McCarthy, J.F., and Houck, J.R. 1979, Ap. J. 233, 611.Google Scholar
Glassgold, A.E. and Huggins, P.J. 1985, Ap. J. submitted.Google Scholar
Glassgold, A.E., Huggins, P.J., and Langer, W.D. 1985, Ap. J. 290, 615.Google Scholar
Glassgold, A.E., Lucas, R., and Omont, A. 1985, Astr. Ap. in press.Google Scholar
Hagen, W., Stencel, R.E., and Dickinson, D.F. 1983, Ap. J. 274, 286.CrossRefGoogle Scholar
Honeycutt, R.K., Bernat, A.P., Kephart, J.E., Gow, C.E., Sandford, M.T., and Lambert, D.L. 1980, Ap. J. 239, 565.Google Scholar
Huggins, P.J. 1984, in “Mass Loss from Red Giants”, Eds. Morris, M. and Zuckerman, B. (Dordrecht: Reidel), p. 161.Google Scholar
Huggins, P.J. and Glassgold, A.E. 1982, Ap. J. 252, 201.Google Scholar
Jennings, M.C. and Dyck, H.M. 1972, Ap. J. 177, 427 (1972).Google Scholar
Jura, M. 1985, Irish Astr. J, in press.Google Scholar
Jura, M. and Morris, M. 1981, Ap. J. 251, 181.CrossRefGoogle Scholar
Lambert, D.L., Brown, J.A., Hinkle, K.H., and Johnson, H.R. 1984, Ap. J. 284, 233.Google Scholar
Mauron, N., Fort, B., Querci, F., Dreux, M., Fauconnier, T., and Lamy, P. 1984, Astr. Ap. 130, 341.Google Scholar
Morris, M. and Jura, M. 1983, Ap. J. 264, 546.Google Scholar
Newell, R.T. and Hjellming, R.M. 1982, Ap. (Letters) 263, L85.CrossRefGoogle Scholar
Omont, A. in “Mass Loss from Red Giants”, Eds. Morris, M. and Zuckerman, B. (Dordrecht: Reidel), p.269.Google Scholar
Omont, A. 1987, these proceedings.Google Scholar
Sopka, R.J., Hildebrand, R., Jaffe, D.T., Gatley, I., Roellig, T., Werner, M.W., Jura, M., and Zuckerman, B. 1985, Ap. J. in press.Google Scholar
Weymann, R.J. 1962, Ap. J. 136, 844.Google Scholar
Zuckerman, B. 1985, private communication.Google Scholar