1999PASP..111..489M

We discuss the slope of the RR Lyrae variables M_v,{lsqb}Fe/H{rsqb} relation by two independent methods. We show that the slope is 0.32 if Baade-Wesselink M_v values are used only for stars with [Fe/H]>-1.5. Because the metal abundances of the variables are constant or nearly so for a large range of periods (the Oosterhoff I variables with log P values in the range -0.29 to -0.215), a flat section in the M_v,{lsqb}Fe/H{rsqb} relation is produced that tends to reduce the slope if stars with log[Fe/H]←1.5 are included in the solution. An analysis of data on RR Lyrae stars in the Galactic bulge yields a slope of ∼0.31.