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Amplitude Variability of Delta Scuti Stars: 4 CVn

Published online by Cambridge University Press:  12 April 2016

Michel Breger
Michel Breger*
Affiliation:
Institut für Astronomie, Universität Wien, Türkenschanzstr. 17, A-1180, Wien, Austria

Abstract

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The amplitude variability of δ Scuti stars is demonstrated by the behavior of the evolved δ Scuti star 4 CVn. The data on 4 CVn covering over 30 yr shows the amplitudes of almost all modes to be extremely variable with a time scales of ten years or longer. The most rapid decrease of amplitude in V is shown by the 7.38 d−1 mode of 4 CVn, which collapsed from 15 mmag in 1974 to 4 mmag in 1976, and 1 mmag in 1977. Between 1974–6 and 1977–8 phase jumps of almost half a cycle occurred. While a simple beating model of two close frequencies can be ruled out from the photometric data, the change is compatible with the growth of a new mode between 1976 and 1977.

Type
Part 6. Variables Close to the Main Sequence
Information
International Astronomical Union Colloquium , Volume 176: The Impact of Large-Scale Surveys on Pulsating Star Research , 2000 , pp. 421 - 425
Copyright
Copyright © Astronomical Society of the Pacific 2000

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