The Trimodal Horizontal Branch of M75 (NGC 6864)
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Date
2002
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Abstract
Deep UBVI photometry for a large field covering the distant globular cluster M75 (NGC 6864) is presented. We confirm a previous suggestion (Catelan et al. 1998) that M75 possesses a bimodal horizontal branch (HB) bearing striking resemblance to the well-know case of NGC 1851. In addition, we detect a third, smaller grouping of stars may correspond to the upper part of a very extended, though thinly populated, blue tail. Thus M75 appears to have a trimodal HB. The presence of the "Grundahl jump" is verified using the broadband U filter.