AB stars in the southern galactic halo. II - Spectroscopy and radial velocities

A spectroscopic study of over two hundred high latitude stars of spectral types A and B which compromise a sample of in situ halo field stars selected without kinematic bias is discussed. Results are presented and discussed in detail for the radial velocities and spectral line measurements of the interstellar K lines, weak metallic lines, Ca II line equivalent widths, and hydrogen lines. Stellar Ca II K line strengths are found to correlate quite well with overall metallicity for all cases except Am stars and high luminosity stars. The K line equivalent widths for all but about five percent of the sample AB stars are normal for metal-poor Population II stars. A few AB stars have near solar metallicities and relatively high radial velocities, but no such stars are found beyond 2-3 kpc from the plane. The large majority of the stars with V = 13.5-15.5 are Population II field blue horizontal branch stars.