Variable stars in Palomar 13; an evaporating globular cluster
  We present new CCD $VI$ photometry of the distant globular cluster Pal 13.
Fourier decomposition of the light curves of the three cluster member RRab
stars lead to estimations of [Fe/H]=-1.65, and a distance of 23.67$\pm$0.57
kpc. Light and colour near minimum phases for RRab stars leads to an estimate
of $E(B-V)$=0.104 $\pm$ 0.001. A $V/(V-I)$ colour-magnitude diagram, built
exclusively with likely star members, shows consistency with the above
parameters and an age of 12 Gyrs. A search of variable stars in the field of
view of our images revealed the variability of a red giant cluster member and
of three probably non-member stars; two RRab stars and one W Virginis star or
CW. The GAIA proper motions of member stars in Pal 13 show a significant
scatter, consistent with the scenario of the cluster being tidally stripped.
