Period Analysis of AAVSO Visual Observations of Semiregular (SR) Variable Stars. II
John R. Percy
Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4, Canada
Received October 26, 2012; revised January 8, 2013; accepted January 8, 2013
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.