The RR Lyrae variable stars in the globular cluster IC 4499

Abstract

Periods and light curves are presented for 75 RR Lyrae variables in the globular cluster IC 4499. Of these, 52 are of the ab type with a mean period of 0.578 + or - 0.009, and 23 are c type with a mean period of 0.351 + or - 0.004. The cluster belongs to Oosterhoff group I (the short-period group) and has the greatest frequency of RR Lyrae variables of the globular clusters in the Galaxy. The distribution of mean fundamentalized period and transition period and their correlation with Fe/H within globular clusters of similar horizontal-branch type to IC 4499 are discussed.