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The Pulsation Properties of the Double-Mode RR Lyrae Variable V79
in Messier 3

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Christine M. Clement
Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON, M5S 3H8, Canada

Mike Thompson
725 Ridgecrest Drive, Colfax, CA 95713

Received March 5, 2007; revised March 21, 2007; accepted March 22, 2007

Abstract: The double-mode RR Lyrae variable V79 in M3 was observed on seven nights in April 2006 with a 14-inch Schmidt-Cassegrain telescope. A total of 275 CCD frames were obtained. An analysis of these observations indicates that the first- overtone period P₁ was 0.3590 day, the fundamental period P₀ was 0.4834 day, and the amplitude ratio A₁/A₀ was 1.00 +/- 0.22. These results imply that the fundamental period increased and that the strength of the fundamental mode oscillations relative to the first-overtone may have increased since 1998 when the star was previously observed. The data also indicate that the periods may fluctuate from cycle to cycle.