paper

Two-epoch orbit estimation for wide binaries resolved in Hipparcos and Gaia

arXiv:2010.03628 · doi:10.3847/1538-3881/abbe1c

Abstract

The Hipparcos catalog and its Double and Multiple System Annex (DMSA) lists 4099 components with individual proper motions and coordinates on the epoch 1991.25. Many of these long-period binary stars are also present in the Gaia Data Release 2 (DR2). Using the available relative positions and proper motions separated by 25.25 years, the equations of relative orbital motion can be solved for the two epoch eccentric anomalies, orbital period, and eccentricity. The method employs elimination of the linear Thiele-Innes unknowns and nonlinear optimization of the remaining condition equations. The quality of these solutions is compromised by the insufficient condition and modest precision of the Hipparcos astrometric data, as revealed by Monte-Carlo simulations with artificially perturbed data points. The presence of multiple systems and optical pairs can also perturb the results. Limited experiments with artificial data indicate that useful estimates can be obtained with a 25-year epoch difference for wide binaries with orbital periods up to years. The prospects of this method dramatically improve with the proposed next-generation space astrometry missions such as Gaia-NIR and Theia, especially when additional conditions are included from astrometric or spectroscopic measurements. A ancillary catalog of cross-identification and astrometric information for 1295 double star pairs cross-matched in Gaia DR2 and Hipparcos is published.

arXiv commentAccepted in the Astronomical Journal. Table 1 with Hipparcos and Gaia DR2 data for 1295 pairs is available online. Minor corrections to make it close to the proofed version

References in corpus (12)