Optimal Eclipsing Binary Systems for Distance Determination
E. B. Lee · The Astronomical Journal · 1997
I develop a method to estimate the errors in fitting the light curves of detached eclipsing binary systems to hypothetical observations. Gravitational microlensing searches will produce a large catalog of binary systems, making it possible to choose optimal systems for follow-up photometry to get accurate radii of the stars. I use a simple model with circular orbits, small eclipse widths, fixed linear limb darkening coefficients, but with variable ``third light'', and I require the eclipse durations to be short. The third light can be determined from the light curve, so field crowding can be handled. In this restricted case the shape of the light curve obeys some simple scaling laws which simplify the multi-dimensional minimization problem, and suggest consistency checks to be used in the process of reducing light curve data. I estimate the fractional error in a determination of the radii of the stars as a function of the binary system configuration. This data is then used to give a range of possible accuracies depending on the eclipse depths. This information then gives an estimate of the photometric accuracy required to get distances with a given precision to objects like globular clusters, the galactic bulge, M31, M33, the SMC, and the LMC.