Kinematics of local RR lyrae stars. I.

The metal-rich tail of the RR Lyrae distribution extends to [Fe/H]_K_{approx}0, and a qualitative analysis of the distribution of distances from the galactic plane shows that the stars in this tail (i.e., [Fe/H]_K_>-1.0) are more concentrated to the plane than the more metal-poor stars. The abundance distribution of the local RR Lyrae stars is in excellent agreement with the changing abundance distributions of distant RR Lyrae stars as a function of galactocentric distance, as derived by Suntzeff et al. (1991ApJ...367..528S), who ascribed this change to systematic variations in horizontal branch morphology (probably age variations) with galactocentric distance.

The abundance distribution of the local RR Lyrae stars also agrees well with those of the distant RR Lyrae stars as a function of distance from the galactic plane. There is no evidence for an abundance gradient in this direction, suggesting that gaseous dissipation did not play a major role in the formation of the outer halo. Addresses: Layden A.C. <alayden@noao.edu> Department of Astronomy, Yale University, P.O. Box 208101 New Haven, Connecticut 06520-8101