Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-12T20:07:57.115Z Has data issue: false hasContentIssue false
  • English
  • Français

Recent Theoretical Results for δ Scuti and Dwarf Cepheid Variables

Published online by Cambridge University Press:  30 March 2016

John R. Percy
John R. Percy*
Affiliation:
Dunlap Observatory and Erindale College , University of Toronto, Toronto, CanadaM5S 1A7

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Recent evidence suggests that δ Set stars and most dwarf Cepheids are population I objects of normal mass. The remaining dwarf Cepheids, including CY Aqr, DY Peg, SX Phe and GD 428, have low masses, are metal-deficient, and are in a presently undetermined stage of evolution (Breger 1979, McNamara and Feltz 1978, but see also Simon 1979).

Many δ Set and dwarf Cepheid variables are multiperiodic and, in principle, multiple periods can be used to infer physical properties of these stars. The component periods must be determined accurately and reliably, and several workers (Breger, Fitch, Kurtz, Pelt, Percy, Shob-brook, Stellingwerf, Stobie and Warman) are active in developing and applying new methods of period analysis; see Wizinowich and Percy (1979) for a representative example.

One result of these analyses is the discovery that in some stars, modes may vary in amplitude or appear or disappear completely within a few days (Stobie and Shobbrook 1976). Methods of period analysis must allow for this possibility if they are to be accurate and reliable.

Type
Joint Discussion
Information
Highlights of Astronomy , Volume 5: Highlights of Astronomy. As presented at the XVIIth General Assembly of the IAU, 1979 , 1980 , pp. 467 - 468
Copyright
Copyright © Cambridge University Press 1980

References

Balona, L.A. and Stobie, R.S. 1979. Monthly Notices Roy. Astron. Soc. 187, 217.Google Scholar
Breger, M. 1979. Publ. Astron. Soc. Pacific 91, 5.Google Scholar
Cox, A.N., King, D.S. and Hodson, S.W. 1979a. Astrophys. J. 228, 870.CrossRefGoogle Scholar
Cox, A.N., King, D.S. and Hodson, S.W. 1979b. Astrophys. J. 221, 798.Google Scholar
Dziembowski, W. 1977a. Acta Astron. 27, 95.Google Scholar
Dziembowski, W. 1977b. Acta Astron. 21, 203.Google Scholar
Fitch, W.S. and Wisniewski, W.Z. 1979. Astrophys. J. 231 808.CrossRefGoogle Scholar
Kurtz, D.W. 1976. Astrophys. J. Suppl. 32, 651.Google Scholar
McNamara, D.H. and Feltz, K.A. 1978. Publ. Astron. Soc. Pacific 90, 275.Google Scholar
Pamjatnykh, A.A. 1973. Nauchn. Informatsii 27, 99.Google Scholar
Pamjatnykh, A.A. 1974. Nauchn. Informatsii 29, 108.Google Scholar
Simon, N.R. 1979. Astron. Astrophys. 75, 140.Google Scholar
Stellingwerf, R.F. 1976. Los Alamos Publication LA-6544-C, 181.Google Scholar
Stellingwerf, R.F. 1979. Astrophys. J. 227, 935.Google Scholar
Stobie, R.S. and Shobbrook, R.R. 1976. Monthly Notices Roy. Astron. Soc. 174, 401.Google Scholar
Wizinowich, P. and Percy, J.R. 1979. Publ. Astron. Soc. Pacific 91, 53.Google Scholar