AAS Meeting #193 - Austin, Texas, January 1999
Session 102. Binary Stars
Display, Saturday, January 9, 1999, 9:20am-4:00pm, Exhibit Hall 1

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[102.12] Lessons from Darwin: Breeding the Best-fit Binary Star

T.S. Metcalfe (University of Texas-Austin)

I have developed a procedure utilizing a Genetic-Algorithm-based optimization scheme to fit the observed light curves of an eclipsing binary star with a model produced by the Wilson-Devinney code. The principal advantages of this approach are the objectivity and the uniqueness of the final result. Although this method is more efficient than other comparably global search techniques, the computational requirements of the code are still considerable. I have applied this fitting procedure to my observations of the W~UMa type eclipsing binary BH~Cassiopeiae. An analysis of V--band CCD data obtained in 1994/95 from Steward Observatory and U-- and B--band photoelectric data obtained in 1996 from McDonald Observatory provided three complete light curves to constrain the fit. In addition, radial velocity curves obtained in 1997 from McDonald Observatory provided a direct measurement of the system mass ratio to restrict the search. The results of the GA-based fit are in excellent agreement with the final orbital solution obtained with the standard differential corrections procedure in the Wilson-Devinney code.


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