Speckle interferometry and orbits of "fast" visual binaries

TL;DR

This study reports speckle interferometry observations of 121 binary systems, refining or computing new orbits, estimating component masses, and resolving two binaries for the first time, advancing understanding of fast orbital motions.

Contribution

It provides new and improved orbital parameters for multiple binaries, including first-time orbit calculations and the resolution of previously unresolved systems.

Findings

Refined orbits for 8 known binaries.

Computed 5 new binary orbits for the first time.

Resolved two astrometric binaries for the first time.

Abstract

Results of speckle observations at the 4.1-m SOAR telescope in 2012 (158 measures of 121 systems, 27 non-resolutions) are reported. The aim is to follow fast orbital motion of recently discovered or neglected close binaries and sub-systems. Here 8 previously known orbits are defined better, two more are completely revised, and five orbits are computed for the first time. Using differential photometry from Hipparcos or speckle and the standard relation between mass and absolute magnitude, the component's masses and dynamical parallaxes are estimated for all 15 systems with new or updated orbits. Two astrometric binaries HIP 54214 and 56245 are resolved here for the first time, another 8 are measured. We highlight several unresolved pairs that may actually be single despite multiple historic measures, such as 104 Tau and f Pup AB. Continued monitoring is needed to understand those enigmatic cases.