Subdwarf studies. II - Abundances and kinematics from medium resolution spectra. III - The halo metallicity distribution

Stars previously identified as having UV excesses are observed at 1-A resolution in the Ca II K-line region. Comparisons of these data with other samples and with Monte Carlo simulations involving a single component halo have yielded estimates of halo velocity dispersions and rotation velocity, corrected for the kinematic biases in the sample. It is suggested that the data are not consistent with a model in which the halo formed from star formation in a dissipating, collapsing cloud; they are, however, reconcilable with the formation of the halo stars by numerous, independently evolving gas clouds. The metallicity distribution of a sample of 372 kinematically selected halo stars is then constructed, with a view to selection effects in the data. Good agreement is noted between the globular cluster metallicity distribution and a stochastic model with a mean of 10 enrichments /fragment. (O.C.)