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Classical Cepheids: Period Changes and Mass Loss

Published online by Cambridge University Press:  12 April 2016

H. Deasy
H. Deasy*
Affiliation:
Dunsink Observatory, Castleknock, Dublin 15, Ireland

Extract

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The period is an ideal parameter for monitoring minute changes in the structure of a star passing through the instability strip, as it can be measured with an accuracy of up to one part per million. The view of Parenago (1956) that only abrupt period changes occur in cepheids is no longer prevalent, and it is generally accepted that random period changes are superposed on the secular variation due to evolution. One possible mechanism for the random fluctuations in period or phase is convection or semiconvection, which Sweigert & Renzini (1979) showed could account for the period changes of RR Lyrae stars. Other mechanisms include the influence of binary companions and mass loss. The latter mechanism forms the basis for a separate study involving the use of IUE spectra to search for evidence of matter being ejected from cepheids.

Type
Part I. Fundamental Parameters
Information
International Astronomical Union Colloquium , Volume 82: Cepheids: Theory and Observations , 1985 , pp. 67 - 70
Copyright
Copyright © Cambridge University Press 1985

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