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arXiv · 1902.08085

Variable stars in Palomar 13; an evaporating globular cluster

M. A. Yepeza·A. Arellano Ferro·K. P. Schroeder·S. Muneer·Sunetra Giridhar·Christine Allen
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Abstract

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.

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M. A. Yepeza, A. Arellano Ferro, K. P. Schroeder, S. Muneer, Sunetra Giridhar, Christine Allen. 2019-02-21. Variable stars in Palomar 13; an evaporating globular cluster. https://arxiv.org/abs/1902.08085

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