RR Lyrae stars and the distant Galactic halo - Distribution, chemical composition, kinematics, and dynamics

Published observational data on 29 outer-Galactic-halo RR Lyr stars (Saha, 1984, and Saha and Oke, 1984) and from other surveys are analyzed to characterize the mass distribution, chemical composition, kinematics, and dynamics of the outer Galaxy (up to galactocentric radius R = 40 kpc). The results are presented in graphs and tables and discussed. Findings reported include a rapid fall-off of RR Lyr density at R = 25 kpc, Fe/H varying from -1.0 to -2.2 (with two stars at -0.5), no net Fe/H gradient in the far halo, and Galactic mass (from dynamical computations) about 3 x 10 to the 11th solar mass within R = 25 kpc.