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Session 45 - Eclipsing Binaries.
Display session, Thursday, January 08
Photometrically determined spectral types of Algol secondaries may be found from the temperature of the primary and the ratio of the surface brightness of the stellar components using light curve analysis. These photometricly derived spectral classifications have been found to be systematically later than those determined directly by spectroscopic spectral typing (Yoon et al., PASP 106, 239.) Modeling of complete BVRI orbital light curves allows a determination of binary inclination, and stellar radii as well as spectral types. Luminosity class can not be determined from spectroscopy of the secondaries during eclipse. Photometric light curve solutions are therefore vital additions to spectroscopic observations of Algols. However, photometric monitoring with sufficient phase resolution and coverage to allow photometric modeling of binaries with several day periods requires many nights of observation. Fortunately, a number of these binaries are bright, allowing such a program to be performed with modest equipment. We present results of BVRI monitoring of Algol binaries in need of photometric solutions. The project has been undertaken with the sponsorship of the NSF to provide research experience for undergraduates, see the poster by McNamara et al. for a description of this program. We present new data on WW Cyg, X Tri, and RV Psc obtained with the New Mexico State University Clyde Tombaugh Campus Observatory 16 inch Meade telescope equipped with a SBIG ST-8 CCD camera and standard BVRI filters. Integration times ranged from 15 sec to 2 min. We present modeling of these data and previously published data using the light curve synthesis program ``Binary Maker 2.0" by D. Bradstreet. We discuss our results in relation to the disagreement between spectroscopically and photometrically determined spectral types.
Program listing for Thursday