Spectroscopically Selected Halo K Giants

The motivation for the study and sample selection are outlined by Ratnatunga & Freeman (1985ApJ...291..260R), while details and analysis of the results will be found in Ratnatunga & Freeman (1989). Three high-galactic latitude fields each of 20 square degrees, designated by their Selected-Area identifications, include the following: SA 141 (l=240,b=-85); SA 189 (277, -50); and SA 127 (272, +38), and have the apparent magnitude range 13 < V < 16 and color range (B-V) > 0.9.

Stars were selected from PDS photographic photometry of Schmidt plates (see Ratnatunga 1983, catalog II/121). K-giant selection used the Mgb+MgH feature at 5100A from digital image analysis of PDS scans of ESO 1-m Schmidt telescope objective-prism spectra with 450 A/mm at H-gamma resolution on IIIa-J plates exposed through a Schott GG475 filter. Luminosity confirmation, line-of-sight velocities, and metallicity were determined from 2-A resolution slit spectra taken with the 4-m Anglo- Australian and 1.9-m Mount Stromlo telescopes.