RR Lyrae variables in Galactic globular clusters: IV. Synthetic HB and RR Lyrae predictions

摘要

We present theoretical predictions concerning horizontal branch stars inglobular clusters, including RR Lyrae variables, as derived from syntheticprocedures collating evolutionary and pulsational constraints. On this basis,we explore the predicted behavior of the pulsators as a function of thehorizontal branch morphology and over the metallicity range Z=0.0001 to 0.006,revealing an encouraging concordance with the observed distribution offundamentalised periods with metallicity. Theoretical relations connectingperiods to K magnitudes and BV or VI Wesenheit functions are presented, bothappearing quite independent of the horizontal branch morphology only with Zgreater or equal than 0.001. Predictions concerning the parameter R are alsodiscussed and compared under various assumptions about the horizontal branchreference luminosity level.