Multiple Period Search for K, M and C Type Semiregular Variables in TÜBITAK National Observatory

Abstract

In this study, periods obtained from long-term multi-bands (Johnson V and R filters) photometric observations of some K, M and C spectral type semiregular (SR) variables obtained with the T40 telescope (40 cm) and SSP5A photometer at TÜBITAK National Observatory (TNO) between 1998 and 2005 were examined. We have found that some of these SR variables have multiple (long and short) periods as appeared mostly from Hipparcos observations; three variables are, for the first time, observed to have a period. The light curves, the variation amplitude in R band and the maximum light Epoch(s) of SR variables were also given. Besides, some difficulties encountered in the long-term observations were also discussed briefly.