Abstract
ABSTRACT We observed thirteen objects first identified by Silbermann and Smith (1995) as being above the red horizontal-branch in the color-magnitude diagram of M15. From vby images taken at CTIO, we used the dereddened metallicity index, mo, to select for metal-poor cluster members. We judge that six out of the original thirteen objects are cluster members: four objects moved back to the red giant or asymptotic giant branches, while two stars remained above the red horizontal-branch. From examination of oxygen-enhanced horizontal-branch sequences, the latter two objects (as well as several other metal-poor objects) are likely to be in a post-horizontal-branch evolutionary stage, evolving towards the asymptotic giant branch. Also, we identify an object which may be a post-AGB or blue-loop star.
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