A Comprehensive, Wide-Field Study of Pulsating Stars in the Carina Dwarf
  Spheroidal Galaxy
  We report the detection of 388 pulsating variable stars (and some additional
miscellaneous variables) in the Carina dSph galaxy over an area covering the
full visible extent of the galaxy and extending a few times beyond its
photometric (King) tidal radius along the direction of its major axis. Included
in this total are 340 newly discovered dwarf Cepheids which are mostly located
~2.5 magnitudes below the horizontal branch and have very short periods (<0.1
days) typical of their class and consistent with their location on the upper
part of the extended main sequence of the younger populations of the galaxy.
Several extra-tidal dwarf cepheids were found in our survey up to a distance of
~1 degree from the center of Carina. Our sample also includes RR Lyrae stars
and anomalous Cepheids some of which were found outside the galaxy's tidal
radius as well. This supports past works that suggests Carina is undergoing
tidal disruption. We use the period-luminosity relationship for dwarf Cepheids
to estimate a distance modulus of 20.17 +/- 0.10 mags, in very good agreement
with the estimate from RR Lyrae stars. We find some important differences in
the properties of the dwarf Cepheids of Carina and those in Fornax and the LMC,
the only extragalactic samples of dwarf Cepheids currently known. These
differences may reflect a metallicity spread, depth along the line of sight
and/or, different evolutionary paths of the dwarf Cepheid stars.
