RR Lyrae Stars in M14 and M15

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Session 63 -- Intrinsic and Cataclysmic Variables
Display presentation, Thursday, 9:20-4:00, Heller Lounge Room

[63.04] RR Lyrae Stars in M14 and M15

N.A.Silbermann, M.J.Harrell, H.A.Smith (Michigan State Univ.)

It is well known that metallicity plays and important role in the number and characteristics of RR Lyrae stars in globular clusters. We are continuing a program of studying the RR Lyrae stars in globular clusters of varying metallicity: NGC 6388, M14, M15, and M53. We present results to date for the metal-poor globular cluster M15 ([Fe/H]=-2.17) and preliminary result for the somewhat metal-rich globular cluster M14 ([Fe/H]=-1.39). We have obtained B, V, and R photometry of the RR Lyrae stars using the MSU 0.6m and the WIRO 2.3m telescopes. New periods for variables in M14 have been determined. We also present new lightcurves for the RR Lyrae stars in M14 and M15. These will be used to study the fourier decomposition parameters and period changes of the variables. Color-magnitude diagrams for M14 and M15 will also be presented.

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