Evidence for an overluminosity of the variable star RR Lyrae, and a revised distance to the LMC

We use theoretical models to establish a tight relationship for the absolute magnitudes of RR Lyrae stars as a function of their periods and Stromgren pseudocolor c(0) (u-v)(0) - (v-b)(0) Applying this to RR Lyr, and comparing the result with the predicted average absolute magnitude for stars of similar metallicity from the same models, yields an overluminosity of 0.064 +/- 0.013 mag in Stromgren y ( and thus similarly in V) for RR Lyr. 0.064 +/- 0.013 Based on a revised value for RR Lyr's trigonometric parallax, and on a newly derived reddening value of, we provide a corrected relationship between average absolute magnitude and me-E( B - V) p 0.015 +/- 0.020 tallicity for RR Lyrae stars that takes RR Lyr's evolutionary status fully into account for the first time. Applying this relationship to the LMC, we derive a revised true distance modulus of. (m - M)(0) 18.44 +/- 0.11.