1995A&A...298..159L

We studied the shape and the quality of light curves of oxygen-rich Semiregular Variables and the occurrence of multiple and variable periods among this group of variables to investigate whether there is any correlation between the subgroups of SRVs described by Kerschbaum & Hron (1992A&A...263...97K) and these parameters. For this purpose we used the data and the light curve references given in the General Catalogue of Variable Stars (4th edition, GCVS4, Cat. II/172). To judge the quality of the light curves we introduced a new quality classification based on the number of observed cycles and the mean number of observations per cycle. We also compared our system with a system based on the subjective impression of the light curve similar to the one used in the GCVS4. It was found that for more than 40% of the objects investigated, the data given in the GCVS4 seem to be based on badly known and insufficient light curves. No correlation between the shape of the light curves and the classification of Kerschbaum & Hron could be found. More objects with multiple or variable periods were found among the objects with very long periods than among the objects with short periods.