A colour-magnitude diagram for the galactic bulge
Date
1986
Authors
Jylänne, Elisabet
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Abstract
A colour-magnitude diagram of 7889 stars brighter than B=l8.0 is obtained for a low-absorption window of approximately one degree centered on the globular cluster NGC 6304 (1=356°, b=-+5°; Z•0.6 kpc). Two plates, (103a-o+GG13 and 103a-D+GG14) taken with the 1.5-m CTIO telescope, were digitized and the data reduced to V magnitudes and B-V colours. The resulting colour-magnitude diagram reflects a range of metallicities but with a strong metal rich component. An excess of bright and of faint blue stars is present; the latter appear to be blue horizontal branch stars. Complementing the blue horizontal branch stars are red horizontal branch stars. At intermediate colour is an excess of stars which may be metal-rich red horizontal branch stars in the disk.