On The Masses And Luminosities Of RR Lyrae Stars

Some results are given from the comparison with observations of a large number of hydrodynamic pulsation models: (1) Linear pulsation calculations are adequate for the determination of the masses of RRd stars; (2) the Fourier phase parameter 4>31 measures the luminosity-to-mass ratio L/M1.81 for RRc stars; (3) most of the w Cen RRc stars seem to be evolved, as has previously been suggested; (4) the masses of the w Cen RRc stars agree with the masses of RRd stars in other clusters; and (5) a hint emerges of a mass-helium abundance relation among the RRc stars in w Cen. New CCD observations will be needed to extend our analysis to additional globular clusters. Subject headings: stars: individual (w Cen) stars: pulsation stars: RR Lyrae