A Search for Faint Blue Stars.

Four-color photography has been used in a search for faint blue stars with the 18-inch Schmidt tele- scope at Palomar, undertaken in the hope of finding new white dwarfs. In this Contribution the results are given for stars brighter than magnitude 15.0 pg in two regions (a) the Hyades clustei; (b) the region of the north galactic pole. Spectroscopic observations have been made with the 100-inch reflector. In the Hyades region fourteen blue stars were found, with spectral types ranging from BO to B5. Proper motions are known for ten of these stars. From their motions and spectra, four are shown to be white dwarfs, three of them physical members of the cluster. Absorption lines are wide and shallow in the spectra of two others, whose motions are not known-an in~1ication that they also may be white dwarfs. In the region of the north galactic pole thirty-one blue stars were found. Their spectra range from BO to AO. Proper motions are available for only four stars, one of which, from its motion and spectrum, is a white dwarf. Two other stars, whose motions are unknown, have spectra similar to those of the white dwarfs. The spectra of the remaining twenty-eight stars appear normal; if these objects are high-lumi- nosity blue stars, their distances are exceedingly large. Possibly they belong to the type of stellar popula- tion shown in the Hertzsprung-Russell diagram for globular clusters and designated by Baade as "Type II." If so, their absolute magnitudes are about 0.0, and their distribution in space would be similar to that of the globular clusters and cluster-type variables