VRI Light Curves of SS 433: Photometry and Model

We present the results of VRI CCD photometric observations of SS 433 and VRI light-curve modelings for SS 433. Observations were carried out in the fall of 1995 using the 51-cm relfector at Osaka Kyoiku University. Three cycles of the binary phase were covered. The mean magnitudes and colors during the observational periods were V = 14.0, R = 11.1, I = 10.5; V - R = 2.88, V - I = 3.50, R - I = 0.62. On October 17 and 18 a strong flare was observed. Theoretical light curves were also calculated using a model in which SS 433 consists of a geometrically thick torus around a compact star and a companion star filling the Roche lobe. In the torus picture VRI light curves were first calculated; for appropriate parameters VRI model light curves well reproduce the observational profiles. In addition, the extinction was first derived from the magnitude difference between the obervation and the model; Av rv 6-7, AR rv 3-4, and AI rv 3. These values are in good agreement with those of a previous observation.