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We performed deep photometry of the central region of Galactic globularcluster M15 from archival Hubble Space Telescope data taken on the HighResolution Channel and Solar Blind Channel of the Advanced Camera for Surveys.Our data set consists of images in far-UV (FUV$_{140}$; F140LP), near-UV(NUV$_{220}$; F220W), and blue (B$_{435}$; F435W) filters. The addition of anoptical filter complements previous UV work on M15 by providing an additionalconstraint on the UV-bright stellar populations. Using color-magnitude diagrams(CMDs) we identified several populations that arise from non-canonicalevolution including candidate blue stragglers, extreme horizontal branch stars,blue hook stars (BHks), cataclysmic variables (CVs), and helium-core whitedwarfs (He WDs). Due to preliminary identification of several He WD and BHkcandidates, we add M15 as a cluster containing a He WD sequence and suggest itbe included among clusters with a BHk population.  We also investigated a subset of CV candidates that appear in the gap betweenthe main sequence (MS) and WDs in FUV$_{140}-$NUV$_{220}$ but lie securely onthe MS in NUV$_{220}-$B$_{435}$. These stars may represent a magnetic CV ordetached WD-MS binary population. Additionally, we analyze our candidate He WDsusing model cooling sequences to estimate their masses and ages and investigatethe plausibility of thin vs. thick hydrogen envelopes. Finally, we identify aclass of UV-bright stars that lie between the horizontal branch and WD coolingsequences, a location not usually populated on cluster CMDs. We conclude thesestars may be young, low-mass He WDs.

UV-Bright Stellar Populations and Their Evolutionary Implications in the Collapsed-Core Cluster M15