Variable Stars in Palomar 13: an Evaporating Globular Cluster (Abstract)
Volume 48 number 1 (2020)
- Mario Alberto Yepez Rivera
- Aile 420, Pedregal de santo domingo, coyoacan, Ciudad de Mexico 4369, Mexico; myepez@astro.unam.mx
- Armando Arellano Ferro
- address correspondence to Mario Alberto Yepez Rivera, Aile 420, Pedregal de santo domingo, coyoacan, Ciudad de Mexico
- Klaus-Peter Schröder
- address correspondence to Mario Alberto Yepez Rivera, Aile 420, Pedregal de santo domingo, coyoacan, Ciudad de Mexico
- S. Muneer
- address correspondence to Mario Alberto Yepez Rivera, Aile 420, Pedregal de santo domingo, coyoacan, Ciudad de Mexico
- Sunetra Giridhar
- address correspondence to Mario Alberto Yepez Rivera, Aile 420, Pedregal de santo domingo, coyoacan, Ciudad de Mexico
- Christine Allen
- address correspondence to Mario Alberto Yepez Rivera, Aile 420, Pedregal de santo domingo, coyoacan, Ciudad de Mexico
Abstract
(Abstract only) We present new CCD V I 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 ± 0.57 kpc. Light and color near minimum phases for RRab stars lead to an estimate of E(B−V) = 0.104 ± 0.001. A V / (V−I) color-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.