OPTICAL COLORS AND METALLICITIES OF GAS-RICH QUIESCENT DWARF GALAXIES

The results of UBVR and Her imaging and moderate resolution optical sp ectroscopy of 28 gas-rich, quiescent dwarf galaxies are presented. The majority of these galaxies are distinguished by unusually high values of hydrogen-mass-to-optical-luminosity, extensive low surface brightn ess structure, and inefficient star formation processes. All are gas-r ich, with typical gas depletion times on the order of 10(11) years. As seen in other studies of dwarf galaxies, the derived oxygen abundance s range from 1/3rd to 1/24th of solar, with typical values between 1/4 th to 1/8th of solar. The observed colors and metallicities will be us ed in the future to constrain the evolutionary status of these star fo rmation inhibited galaxies. (C) 1997 The American Astronomical Society . [S0004-6256(97)04512-3].