New Blue and Red Variable Stars in NGC 247
  Images recorded with the Gemini Multi-Object Spectrograph (GMOS) on Gemini
South are combined with archival images from other facilities to search for
variable stars in the southern portion of the nearby disk galaxy NGC 247.
Fifteen new periodic and non-periodic variables are identified. These include
three Cepheids with periods < 25 days, four semi-regular variables, one of
which shows light variations similar to those of R CrB stars, five variables
with intrinsic visible/red brightnesses and colors that are similar to those of
luminous blue variables (LBVs), and three fainter blue variables, one of which
may be a non-eclipsing close binary system. The S Doradus instability strip
defines the upper envelope of a distinct sequence of objects on the (i', g'-i')
color-magnitude diagram (CMD) of NGC 247. The frequency of variability with an
amplitude > 0.1 magnitude in the part of the CMD that contains LBVs over the
seven month period when the GMOS images were recorded is ~ 0.2. The light curve
of the B[e] supergiant J004702.18--204739.9, which is among the brightest stars
in NGC 247, is also examined. Low amplitude variations on day-to-day timescales
are found, coupled with a systematic trend in mean brightness over a six month
time interval.
