Visual Orbits & Alignments of Planet Hosting Binary Systems

TL;DR

This study measures the orbits of binary star systems hosting transiting exoplanets, revealing that their orbital planes are generally aligned, which informs theories of planet formation in multi-star environments.

Contribution

It provides new high-resolution astrometric measurements of 13 binary systems with transiting planets, enhancing understanding of orbital alignments in close binary systems.

Findings

Mutual inclination between binary and planetary orbits is generally well aligned.

Results complement previous Gaia data for wider binaries.

Supports theories of planet formation in aligned binary systems.

Abstract

Roughly half of Solar-type planet hosts have stellar companions, so understanding how these binary companions affect the formation and evolution of planets is an important component to understanding planetary systems overall. Measuring the dynamical properties of planet host binaries enables a valuable test of planet formation in multi-star systems and requires knowledge of the binary orbital parameters. Using high resolution imaging, we have measured the relative astrometry and visual orbits of 13 binary systems where one of the stars is known to host a transiting exoplanet. Our results indicate that the mutual inclination between the orbits of the binary hosts and the transiting planets are well aligned. Our results for close binary systems (a<100 AU) complement past work for wide planet host binaries from Gaia.