Binary-star light curve models

Abstract

The historical development of binary-star light-curve models is traced from the early 1900s to the present, with emphasis on recent progress. A major break with tradition occurred about 1970 when physical models, based on equipotentials and made possible by fast computers, replaced geometrical models. Physical models have been improving in accuracy, efficiency, generality, and user friendliness. Further improvements can be expected. Astrophysical advances due to the new models range from new ways to estimate mass ratios and rotation rates to confirmation of theoretical predictions about the structure of W Ursae Majoris stars and behavior of irradiated convective envelopes. The morphology of close binaries, including extensions to nonsynchronous rotation and orbital eccentricity, is interwoven with physical models and their applications. The origins and influence of the four morphological types-detached, semidetached, overcontact, and double contact-are inseparable from the development of light-curve models. Parameter adjustment is an active area, with contributions on Differential Corrections, the Marquardt algorithm, the Simplex algorithm, and other methods for reaching a least-squares minimum. Solutions with applied constraints and simultaneous solutions of two or more kinds of observations are coming into more frequent usage. Observables other than photometric brightness include radial velocity, polarization, photospheric spectral line profiles, and spectral distributions due to circumstellar flows. Some of the newer models extend into these areas and are leading to new kinds of observing programs.

A Charge-Coupled Device Photometric Study of South Hemispheric Contact Binary Ae Phoenicis

“…In order to obtain photometric solutions and understand the evolutionary state of the binary system, we analyze the present B, V, R, and I light curves with the fourth version of the W-D code (Wilson & Devinney 1971;Wilson 1990Wilson , 1994Wilson & Van Hamme 2003). The temperature of star 1 (star eclipsed at primary light minimum) was chosen as T 1 = 6310 K (Barnes et al 2004).…”

Close binary and other variable stars in the solar-age Galactic open cluster M 67

“…The light curve analysis of the system has been made by using the WD code in Mode 3 (Wilson & Devinney 1971;Wilson 1994). The adopted values are: T 1 = 6300 K from the B − V colour index, gravity darkening coefficients, and albedos were chosen as g 1 = g 2 = 0.32 (Lucy 1967) and A 1 = A 2 = 0.5 (Rucinski 1969) and the logarithmic limb-darkening coefficients (x 1 , x 2 ) were obtained from van Hamme (1993).…”

The asymmetric light curves of the GSC 2764 1417 (And), GSC 3355 0394 (Per) and GSC 2537 0520 (Psc)

“…Times of minima were calculated, period studies were carried out and orbital behaviors were determined and used to phase present light curves. B,V,R,I light curves were hand premodeled with Binary Maker 3.0 (Bradstreet 2002 (Wilson & Devinney 1971, Wilson, 1990, Wilson 1994, Van Hamme & Wilson 1998). …”