The PHASES Differential Astrometry Data Archive. III. Limits to Tertiary Companions

TL;DR

This study uses high-precision astrometry to search for and set limits on the presence of tertiary companions, such as Jovian planets, in binary star systems, providing new constraints on their possible existence.

Contribution

Introduces a novel algorithm for detecting and excluding tertiary companions in binary systems using PHASES data, and maps the excluded mass-period parameter space.

Findings

No evidence of tertiary companions in 21 monitored systems.

The algorithm effectively constrains the presence of companions across specific mass and period ranges.

Provides detailed exclusion regions for potential companions in 21 binary systems.

Abstract

The Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) monitored 51 subarcsecond binary systems to evaluate whether tertiary companions as small as Jovian planets orbited either the primary or secondary stars, perturbing their otherwise smooth Keplerian motions. Twenty-one of those systems were observed 10 or more times and show no evidence of additional companions. A new algorithm is presented for identifying astrometric companions and establishing the (companion mass)-(orbital period) combinations that can be excluded from existence with high confidence based on the PHASES observations, and the regions of mass-period phase space being excluded are presented for 21 PHASES binaries.