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 o .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.

Estimating masses of selected stars in the Pulkovo program by means of astrometry methods

“…Finally with the mass-ratio B value of 0.48 we obtained a minimum of E 0 equal to 0 ′′ .032 and the mass of the components of 0.57 and 0.53M ⊙ that is satisfactory to spectral classes of components. In the table the sum of mass is given according to our estimate, see Shakht et al (2010), n-the number of used plates, X,Y -the average result from X,Y axis projections.…”

“…Fig. 1 The course with the time of coordinates X j ,Y j of ADS 8035A in mas Determination of orbit and the estimation of mass were made at Pulkovo,see Shakht et al (2010), however observational arc is enough short. In the solving classical equations ( 5), there were correlations between unknowns and they hardly separated.…”

“…Determination of the orbit and estimation of masses were made at Pulkovo, see Shakht et al (2010), however the observational arc is quite short. In solving the classical dynamics in Equation ( 5), there were correlations between unknowns and they hardly separated.…”

“…In Table 5, the sum of masses is given according to our estimate, see Shakht et al (2010), n is the number of used plates, and X, Y are the average result from projections onto the X, Y axes, respectively.…”

Astrometric observations of visual binaries using 26‐inch refractor at Pulkovo Observatory during 2014–2019

“…First, using these two approaches simultaneously allowed us to derive systematic differences in relative positions, which in some cases exceed random errors significantly. Second, this framework enabled the determination of the orbits of visual binaries using the apparent motion parameters (AMP) method back in 2009–2012 (Kiselev & Romanenko 2011; Kiselev et al 2009, 2012; Kisselev et al 2009; Romanenko & Kiselev 2014; Shakht et al 2010). If only the results of CCD‐observations were used, the orbit determination would have been postponed.…”