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

Volume 35 number 2 (2007)

Download this article (pdf)

Christine M. Clement

Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON,

Mike Thompson

725 Ridgecrest Drive, Colfax, CA 95713

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.