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Two-Color Photometry of the Double-Mode RR Lyrae Star NSVS 5222076

Volume 37 number 1 (2009)

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David A. Hurdis
76 Harbour Island Road, Narragansett, RI 02882

Abstract

Observations of double-mode RR Lyrae stars are especially useful to modelers because their two independent pulsation periods allow a unique determination of the star's mass. Only recently identified as an RRd field star, NSVS 5222076 is bright and well-placed for Northern Hemisphere observers. Photometry time-series data were acquired in both the V and I bands. The V data, when combined with those of Oaster, Smith, and Kinemuchi (2006), allowed the periods to be determined more precisely as P0 = 0.49405 day and P1 = 0.36690 day. The amplitude ratio, A0/A1, was found to be about 1.4. Time variation of V-I color was also determined.