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Bulgarian Journal of Physics
Print: 1310-0157 Online: 1314-2666
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RECOGNIZED BY THE EUROPEAN PHYSICAL SOCIETY 
Bulg. J. Phys. vol.28 no.3-4 (2001), pp. 175-184
Variable Stars in the Outer-halo Globular Cluster Palomar 3
J. Borissova1, N. Spassova1, V. Ivanov2
1Institute of Astronomy, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd. 1784 Sofia, Bulgaria
2Steward Observatory, University of Arizona, Tucson, AZ 85721, USA
go back1Institute of Astronomy, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd. 1784 Sofia, Bulgaria
2Steward Observatory, University of Arizona, Tucson, AZ 85721, USA
Abstract. We present the time-series V and 1 photometry of the outerhalo globular cluster Palomar 3, which has been obtained with a purpose of providing the extensive CCD variability study of this cluster. As a result, we have confirmed the variability of the RR Lyr star candidate of Burbidge and Sandage (1958), the RR Lyr star suspected by Gratton and Ortolani (1984) and the Population II Cepheid. Seven new suspected variables are presented. For the first time we determine the period P = 3.402 days and the light curve of the Population II Cepheid. As well known, Population II Cepheids are usually found in clusters with well-developed blue-HB tails only, so their presence in such a red-HB cluster as Palomar 3 is extremely puzzling.