Stellar Populations in the Phoenix Dwarf (dIrr/dSph) Galaxy as Observed   by HST/WFPC2
  We present HST/WFPC2 photometry of the central regions of the Phoenix dwarf. Accurate photometry allows us to: 1) confirm the existence of the horizontal branch previously detected by ground-based observations, and use it to determine a distance to Phoenix, 2) clearly detect the existence of multiple ages in the stellar population of Phoenix, 3) determine a mean metallicity of the old red giant branch stars in Phoenix, and suggest that Phoenix has evolved chemically over its lifetime, 4) extract a rough star formation history for the central regions which suggests that Phoenix has been forming stars roughly continuously over its entire lifetime. 
Jon A. Holtzman (NMSU), Graeme H. Smith (UCO/Lick), Carl Grillmair   (SIRTF Science Center)