Period Analysis of AAVSO Visual Observations of Semiregular (SR) Variable Stars. II

Volume 41 number 1 (2013)

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John R. Percy

Department of Astronomy and Astrophysics, University of Toronto. Toronto, ON M5S 3H4, Canada; john.percy@utoronto.ca

Tomas Kojar

Department of Astronomy and Astrophysics, University of Toronto. Toronto, ON M5S 3H4, Canada; john.percy@utoronto.ca

Abstract

We have used visual measurements from the AAVSO International Database, and Fourier and self-correlation analysis to study the periodicity of 44 pulsating red giants, classified as semiregular: 16 SR, 15 SR:, 12 SRb, and one misclassified RV:. Within each of the three groups, the average degree of periodicity (or regularity) is about the same and there is a wide variety of behavior, from irregular to highly periodic. About a dozen stars show definite or possible double-mode pulsation, and half a dozen show evidence of a long secondary period.