Identification of a new relatively old star cluster in the Small
  Magellanic Cloud
  We present results on the age and metallicity estimates of the astonishingly
unstudied SMC cluster ESO 51-SC09, from CCD BVI photometry obtained at the ESO
NTT with the EMMI attached. ESO 51-SC09 turns out to be a relatively small
cluster (FWHM = (10 +- 1) pc) located ~ 4 deg northward from the galaxy center.
We report for the first time a mean cluster age of (7.0 +- 1.3) Gyr and a mean
cluster metallicity of [Fe/H] = (-1.00 +- 0.15) dex, concluding that ESO
51-SC09 belongs to the group of the oldest SMC clusters. We found that the
cluster is projected onto a dominant field stellar population older (age ~
10-13 Gyr) and more metal-poor ([Fe/H] = -1.3 +- 0.2 dex), so that the cluster
could reach its current location because of its orbital motion.
