Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-30T02:38:17.301Z Has data issue: false hasContentIssue false
  • English
  • Français

A Preliminary Investigation of Period Changes For W Virginis Stars in Globular Clusters

Published online by Cambridge University Press:  12 April 2016

Christine M. Coutts
Christine M. Coutts*
Affiliation:
David Dunlap Observatory, University of Toronto, Richmond Hill, Ontario, Canada

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.

Investigations in recent years have shown that there may be two mechanisms which place stars in the W Virginis instability region (Kraft, 1972). The variables with periods less than 8 days seem to be in the stage of ‘above horizontal branch’ evolution discussed by Strom et al. (1970). The longer period group apparently results when thermal instabilities in the helium burning shell of an asymptotic red giant branch star cause it to loop to the left in the HR diagram. This longer period group has been investigated by Schwarzschild and Härm (1970) and Mengel (1972). The present study has been undertaken to see if there are any notable differences between the period changes of variables belonging to the two groups.

Type
Part III / Slow Variables in Population II Systems
Information
International Astronomical Union Colloquium , Volume 21: Variable Stars in Globular Clusters and in Related Systems , August 1973 , pp. 145 - 149
Copyright
Copyright © Reidel 1973

References

Bailey, S. I.: 1902, Harv. Ann. 38, 1.Google Scholar
Coutts, C. M. and Sawyer Hogg, H.: 1972a, Bull. Am. Astron. Soc. 4, 217.Google Scholar
Coutts, C. M. and Sawyer Hogg, H.: 1972b, in press.Google Scholar
Demers, S. and Wehlau, A.: 1971, Astron. J. 76, 916.Google Scholar
Dickens, R. J. and Carey, J. V.: 1967, Roy. Observ. Bull., No. 129.Google Scholar
Eggen, O. J.: 1961, Roy. Observ. Observ. Bull., No. 29.Google Scholar
Kraft, R. P.: 1972, in Davis Philip, A. G. (ed.), The Evolution of Population II Stars, Dudley Obs. Reports No. 4.Google Scholar
Kwee, K. K.: 1967, Bull. Astron. Inst. Neth. Suppl. 2, 97.Google Scholar
Martin, W. Chr.: 1938, Ann. Sterrew. Leiden 17, pt. 2, 1.Google Scholar
Mengel, J. G.: 1972, IAU Colloq. No. 21, Toronto.Google Scholar
Osborn, W.: 1969, Astron. J. 74, 108.Google Scholar
Poole, L.: 1968, Master’s Thesis, University of Toronto.Google Scholar
Sawyer, H. B.: 1931, Harv. Circ., No. 366.Google Scholar
Sawyer, H. B.: 1935, Publ. Dom. Astrophys. Obs., Victoria 6, 265.Google Scholar
Sawyer Hogg, H. and Wehlau, A.: 1966, Publ. David Dunlap Obs. 2, 451.Google Scholar
Sawyer Hogg, H. and Wehlau, A.: 1968, Publ. David Dunlp Obs. 2, 493.Google Scholar
Schwarzschild, M. and Härm, R.: 1970, Astrophys. J. 160, 341.Google Scholar
Strom, S. E., Strom, K. M., Rood, R. T., and Iben, I.: 1970, Astron. Astrophys. 8, 243.Google Scholar
Wilkens, H.: 1967, Mitt, veränderl. Sterne 4, 93.Google Scholar