Color-magnitude studies of globular clusters. I - The bright stars in NGC 362

UBV photometric data for the southern globular cluster NGC 352 are presented, including photoelectric photometry of 89 sequence stars and a color-magnitude analysis down to a limiting V magnitude of approximately 16.6 (about 1 magnitude below the horizontal branch). It is suggested that NGC 352 is in the intermediate to moderately metal-rich range. Various fine-structure features of the color-magnitude diagram are described and analyzed. It is found that: (1) the red horizontal branch has an extremely sharp lower boundary and diffuses upward toward brighter magnitudes; (2) the asymptotic branch is clearly separated from the giant branch over the short V-magnitude interval from 15 to 14 but seems either to cut off or to merge indistinguishably with the giant branch at brighter levels; and (3) the distribution of stars along the giant branch is visibly nonuniform. The shape of the red horizontal branch is shown to represent plain evidence of stellar evolution from the zero-age horizontal branch toward the base of the asymptotic branch.