The orbits of visual binary and multiple stars obtained by the Apparent Motion Parameters method during the last 40 years

TL;DR

This paper presents 40 years of work on the orbits of 67 wide binary and multiple stars using the Apparent Motion Parameters method, incorporating Gaia DR2 data and analyzing discrepancies suggesting inner subsystems.

Contribution

It provides a comprehensive set of AMP-derived orbits for 67 stars, compares them with new observations and Gaia data, and discusses implications of observed motion discrepancies.

Findings

Orbits for 67 stars were determined using AMP method.

Discrepancies found in 20 cases suggest possible inner subsystems.

Gaia DR2 data helped refine 16 star orbits.

Abstract

Summed many years of work at Pulkovo, the orbits of 67 wide pairs of visual double and multiple stars (included in 64 systems) which were obtained by the Apparent Motion Parameters (AMP) method are presented. This short arc determination orbit method is based on the most reliable astrometric and astrophysical data corresponding to one instant of time. The rest of the observations accumulated in the world serve to control the quality of the orbit and refine some parameters. All early determined AMP-orbits were compared with new observations, some of them were recalculated, new ones were added. For the stars of Pulkovo program of observations with a 26-inch refractor, the Gaia DR2 data were analised. Based on these data, the orbits of 16 stars were calculated. In 20 cases from 67, the quasi-instant motion according to the Gaia DR2 data at the instant 2015.5 contradicts the motion according to all-world observations. A possible reason is the presence of inner subsystems. The orientation of the obtained orbits in the galactic coordinate system is also given.