| Abstract | Deep charge-coupled device images of a field in IC 1613 away from the star forming central regions were taken with the "4-shooter" on the Hale 5 m telescope, and processed to find and photometrically measure variable stars. 15 RR Lyrae stars were found, and periods, light curves, and finding charts for them are presented. The mean magnitude of RR Lyrae stars in this galaxy is deduced to be = 24.90 mag. Assuming the absolute g magnitude for RR Lyraes to be M_g_ = 073 mag, and using extinction A_g_ = 0.07 mag, a distance modulus of 24.10+/-0.27 mag is derived. The finding of RR Lyrae stars indicates the unambiguous presence of an old population. The distance modulus derived from them is smaller than that derived from the Cepheids by an amount which is dependent upon the RR Lyrae zero-point calibration adopted, and may be as large as 0.3 mag. The difference has the same sense and magnitude as the discrepancy in the Large Magellanic Cloud. The probable sources of the problem are discussed. |
