ON THE ABSOLUTE MAGNITUDE OF RR LYRAE STARS - UU CETI, RV PHOENICIS, AND W-TUCANAE

We present infrared JHK light curves for the RRab Lyrae stars UU Ceti, RV Phoenicis, and W Tucanae. These stars have similar periods, approximately 0.d6, and metallicities [Fe/H] approximately -1.00, -1.50, and -1.35, respectively. The infrared data, together with BVRI photometry and CORAVEL radial velocity data previously published by two of us, and Walraven photometry by Lub, are used to derive absolute magnitudes for the stars using two formulations of the Baade-Wesselink method: (1) the infrared flux version and (2) the surface brightness version. The two methods are directly compared and their respective advantages and shortcomings are discussed. Finally, a comparison is made with previous results on the absolute magnitude of RR Lyrae variables.