The PHASES Differential Astrometry Data Archive. II. Updated Binary Star Orbits and a Long Period Eclipsing Binary

TL;DR

This paper combines high-precision and lower-precision astrometric data to refine binary star orbits, revealing potential eclipses in a long-period binary system and predicting the next eclipse date.

Contribution

It provides improved visual orbits for 20 binary stars by integrating diverse measurements, including the first prediction of an eclipse in a long-period binary.

Findings

Refined orbits for 20 binary stars.

Predicted an upcoming eclipse of alpha Com.

Identified potential eclipses despite long orbital periods.

Abstract

Differential astrometry measurements from the Palomar High-precision Astrometric Search for Exoplanet Systems have been combined with lower precision single-aperture measurements covering a much longer timespan (from eyepiece measurements, speckle interferometry, and adaptive optics) to determine improved visual orbits for 20 binary stars. In some cases, radial velocity observations exist to constrain the full three-dimensional orbit and determine component masses. The visual orbit of one of these binaries---alpha Com (HD 114378)---shows that the system is likely to have eclipses, despite its very long period of 26 years. The next eclipse is predicted to be within a week of 2015 January 24.