A NEW, COMPLETE SAMPLE OF FAINT B-STARS IN THE GALACTIC HALO

A new sample of 31 faint B and A0 stars is reported, 30 of which compr ise a complete sample within the limits (U-V)< 0 and 10.0 less than or similar to B 18.0. The sample is based on low-and intermediate-resolu tion spectrophotometry of colour-excess objects selected in the US sur vey. Atmospheric parameters for the stars are derived through the use of synthetic colours, Balmer-line strengths, and model-atmosphere fitt ing. The atmospheric parameters and preliminary metallicity estimates indicate that most of the stars are distributed along the blue horizon tal branch, with low metallicities ([Fe/H] similar to -1.0) and with b oth the first and second Newell gaps present. However, nine of the B/A 0 stars can be identified as candidate main-sequence stars, based on e vidence of high metallicities ([Fe/H] similar to 0) and/or derived eff ective temperatures and surface gravities which place them close to th e main-sequence relation. The completeness characteristics of the samp le are discussed, and its surface density is compared to that of other recently isolated B-star samples. The sample exhibits a shallow integ ral number-count slope. This new sample will help provide increased st atistical coverage of the B-star population in the Galactic halo throu gh its relatively faint magnitude-completeness limits and its relative ly red colour-completeness limit.