Long-term speckle interferometric monitoring of binary systems II: 2007-2025 positional measurements and improvement of orbits

This article is focused on the analysis of observational data and improvement of orbital solutions of 8 objects. The listed objects are members of a sample of approximately 300 nearby (d < 100 pc) multiple systems compiled for long-term monitoring at the 6-meter telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. Speckle interferometric observations were carried out from 2007 to the present, which corresponds to 19 years of monitoring of the systems. Therefore, the new measurements are more numerous than or comparable to those in the literature, which makes it possible to make the observation series more complete. A long observation series made it possible to cover from 20% to 70% of the phases of the orbital periods of the objects under study. In combination with previously published data, the percentage of orbital coverage by measurements ranged from 45% to 85%. As a result, 4 orbits were classified as "definitive", one as "good", 2 as "reliable", and one as "preliminary" according to a grading scheme suggested by W.I. Hartkopf et al. Despite the high grades of the orbital solutions, it is recommended to continue monitoring (in particular, to obtain periastron observations) for HIP 1055, HIP 2532, HIP 15633, HIP 19472 and HIP 20751 in order to derive the final orbital parameters. It is not possible to obtain an accurate orbital solution for HIP 20227 due to measurements whose assigned weight strongly influences the period value, and for HIP 21710(Aa,Ab) due to the long orbital period (Porb > 200 yr) and, consequently, the lack of observational data. An analysis and comparison of the mass sums and masses of components obtained by two independent methods and based on several parallax values were also carried out. In most cases, the best agreement is found between fundamental parameters calculated using Gaia parallaxes, if available.