Analysis of BVI Photometry of the Eclipsing Binary EV Lyrae

Volume 36 number 1 (2008)

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Jerry D. Horne

3055 Lynview Drive, San Jose, CA 95148

Abstract

Differential photometry of the previously little-observed semi-detached eclipsing binary EV Lyr from the 2006 observing season is presented and analyzed. This study utilized a 25-cm SCT instrument to observe portions of 116 orbital cycles and obtain B-, V-, and I-band photometry. This allowed the development of a complete phase diagram of the system and determination of the period of 0.91847 ±0.0002 day and HJD epoch 2453894.71997. Visual band photometric observations were fit to a binary star model phase diagram using the binary star modeling program nightfall. Derived properties for the primary were M/Msun = 1.6, R/Rsun = 1.64, spectral type F0 V, and effective temperature of 7300 K. Derived properties for the secondary were M/Msun = 0.79, R/Rsun = 0.78, spectral type K0 V, and effective temperature of 5200 K. Inclination for the system was found to be 88°.