A search for variable stars in the globular cluster M3 |
| |
| Authors: | Kaluzny Hilditch Clement & Rucinski |
| |
| Institution: | Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland,;School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS,;Department of Astronomy, University of Toronto, Toronto, Ontario M5S 3H8, Canada,;Canada–France–Hawaii Telescope Corporation, PO Box 1597, Kamuela, HI 96743, USA |
| |
| Abstract: | We describe here the results of a photometric time-sequence survey of the globular cluster M3 (NGC 5272), in a search for contact and detached eclipsing binary stars. We have discovered only one likely eclipsing binary and one SX Phe-type star in spite of monitoring 4077 stars with V < 20.0 and observing 25 blue straggler stars (BSS). The newly identified SX Phe star, V237, shows a light curve with a variable amplitude. Variable V238 shows variability either with a period of 0.49 d or with a period of 0.25 d. On the cluster colour–magnitude diagram, the variable occupies a position a few hundredths of a magnitude to the blue of the base of the red giant branch. V238 is a likely descendant of a binary blue straggler. As a side result we obtained high-quality data for 42 of the previously known RR Lyrae variables, including 33 of Bailey type ab, seven type c and two double-mode pulsators. We used equations that relate the physical properties of RRc stars to their pulsation periods and Fourier parameters in order to derive masses, luminosities, temperatures and helium parameters for five of the RRc stars. We also tested equations that relate the Fe/H], M V and temperature of RRab stars to pulsation period and Fourier parameters. We derived Fe/H]= ?1.42 in good agreement with spectroscopic determinations. |
| |
| Keywords: | binaries: eclipsing blue stragglers stars: horizontal branch stars: variables: other globular clusters: individual: M3 |
|
|
