The Age of Computational Astrophysics

Significant progress was made in the early 1970s. Models and programs were developed to compute (synthetic) light and velocity curves directly. Such models and programs were based on spherical stars, treated in EBOP, the Eclipsing Binary Orbit Program [Nelson & Davis (1972), Etzel (1981), and Etzel (1993)]; ellipsoidal geometry, treated in WINK developed by Wood (1971) and newer versions of EBOP. Lucy (1968), Hill & Hutchings (1970), Wilson & Devinney (1971), and Mochnacki & Doughty (1972a, b) produced models and programs based on Roche

17 Ellipses in this column indicate parameters not derived by Carr. Entries in the adjacent following column were determined from Carr's (1972) data with the WD program by Milone et al. (1991) and Milone (1993, p. 197-199).

18 As elsewhere in this volume, a value in parentheses following a quantity specifies the uncertainty in that quantity in units of the last decimal place. The uncertainty given is the mean standard error (m.s.e.), or standard deviation, unless indicated otherwise.

19 Assumed and unadjusted.

geometry. Lucy's was probably the first attempt at direct calculation of light curves; it was limited to over-contact systems describable by a single value of the potential. Only bolometric light curves were computed and effects of mutual irradiation were neglected. Hill and Hutchings provided an early calculation of irradiation effects, assuming a spherical primary for Algol. These new approaches permitted the computation of light curves on the basis of complex physical models describing the dynamic forces controlling the stellar mass distributions and the radiation transport in the components' atmospheres. Physical models based on equipotentials and Roche geometry are implemented in the Wilson-Devinney program [Wilson & Devinney (1971), Wilson (1979)] and in LIGHT2 [Hill & Rucinski (1993) and citations contained therein]; see Section 6.3 for more references of the Roche modelbased programs. Inversely, the development of physical models and programs for EBs led to least-squares determinations of light curve parameters. The first use of least-squares for a physical light curve model was by Wilson & Devinney (1971, 1972, 1973); the next was Lucy (1973). The computational implementation of Roche models coupled with least-squares analyses really started the age of computational astrophysics in EB research.

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