Orbit determination and estimate of the component masses

Abstract

Photographic observations of the visual binary star ADS 7251 were made from 1962 through 2006 on the 26-inch refractor at the Pulkovo Observatory. 206 plates were obtained and used to derive about 3000 relative positions. A uniform series of positions of the B-A components of ADS 7251 with errors in one annual average distance ρ and position angle θ of ±0".006 and ±0°.02, respectively, have been used to determine the elements of the orbit and the sum of the masses of the components. The orbit has been determined using a method of apparent motion parameters developed at Pulkovo. The positions and motions of the components A and B relative to a system of reference stars have also been calculated from 146 of the plates; this made it possible to determine the position of the center of mass and the ratio of the masses of the components. The masses of A and B are 0.57 M ⨀ and 0.53 M ⨀ , respectively, a result that is consistent with their spectral classes and does not indicate the presence of significant excess mass.