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Search for a Secondary Frequency in the Large-Amplitude δ Scuti Star CY Aqr

Published online by Cambridge University Press:  15 February 2018

D. Coates ,
J. Fernley ,
K. Sekiguchi ,
T. G. Barnes  and
M. Frueh
D. Coates
Affiliation:
Department of Physics, Monash University, Clayton, Victoria, Australia
J. Fernley
Affiliation:
IUE-Vilspa, P.O. Box 50727, 28080 Madrid, Spain
K. Sekiguchi
Affiliation:
South African Astronomical Observatory, P.O. Box 9, Cape, South Africa
T. G. Barnes
Affiliation:
McDonald Observatory, University of Texas at Austin, Austin, Texas
M. Frueh
Affiliation:
McDonald Observatory, University of Texas at Austin, Austin, Texas

Abstract

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The large-amplitude δ Scuti star CY Aqr was observed from sites in the U.S.A., South Africa and Australia during August 1988. Coates et al. (1991) published 48 new times of maximum light derived from these observations and assembled, from the literature, previous times of maximum light. It is clear that the period of the star is changing with the balance of evidence favouring discrete changes in 1951 and 1966, rather than a continuous change.

It has been suggested by Fitch (1973) and Else (1972), from an analysis of the observations of Zissell (1968), that there is a secondary frequency present in CY Aqr. Coates et al. (1992) have analysed both the 1988 observations and those of Zissell. After subtracting the primary frequency and its harmonics, they find no stable secondary frequency above the noise level of two millimagnitudes.

Type
Stellar Seismology
Information
International Astronomical Union Colloquium , Volume 139: New Perspectives on Stellar Pulsation and Pulsating Variable Stars , 1993 , pp. 150
Copyright
Copyright © Cambridge University Press 1993

References

Coates, D.W., Barnes, T.G., Fernley, J.A., Frueh, M.L., Sekiguchi, K., 1991, Delta Scuti Star Newsletter 4, 10 Google Scholar
Coates, D.W., Fernley, J.A., Sekiguchi, K., Barnes, T.G., Frueh, M.L., 1992, MNRAS, submittedGoogle Scholar
Elst, E.W., 1972, A&A 17, 148 Google Scholar
Fitch, W.S., 1973, A&A 27, 161 Google Scholar
Zissell, R., 1968, AJ 73, 696 Google Scholar