PERIOD CHANGE RATES FOR 46-RR-LYRAE STARS IN NGC-7006

Period change rates are presented for 46 RR Lyrae stars in the globular cluster NGC 7006 based on previously published photometry of photographic plates taken in the 1930's and 1950's by Hubble and Sandage, and new photometry of 35 photographic plates taken in 1984 with the Palomar 60 in. telescope. The mean period change rate for the 42 RRab stars is [beta] = - 0.06 +/- 0.04 d/Myr and the median is - 0.04, which, for the horizontal branch (HB) type of NGC 7006, is one standard error below the median value of beta predicted by the Yale evolutionary HB models. Statistically significant evidence for a radial gradient in the [beta] values (in the sense that the beta-values are more negative in the outer region of the cluster than in the inner) is also presented and discussed.