The surface-brightness anomaly in eclipsing binaries

Surface-brightness ratios of the eclipsing binaries V477 Cyg, TX Her, CM Lac, RR Lyn, and EE Peg are determined from new V, R light curves. Along with the previously determined values for IQ Per, these ratios are used as probes for the B-V and V-R surface-brightness calibrations in a region of low data density. An anomaly is found in the sense that if the primaries are assumed to lie on the calibration curve, then the secondaries are less bright than expected, or if the secondaries are assumed to lie on the calibration curve, then the primaries are brighter than expected. It does not seem possible at this time to find an unambiguous interpretation of this anomaly. (Author)