Resolving the Multiplicity of Exoplanet Host Stars in Gemini/NIRI Data

TL;DR

This study uses Gemini/NIRI adaptive optics imaging and Gaia astrometry to identify stellar companions to exoplanet host stars, revealing both known and previously unresolved companions to better understand planetary system architectures.

Contribution

It introduces a combined approach of imaging and astrometry to detect stellar companions in exoplanet systems, including unresolved ones, using archival data and Gaia measurements.

Findings

Detected three known stellar companions.

Identified two systems with likely unresolved companions.

Demonstrated the effectiveness of combined imaging and astrometry methods.

Abstract

The majority of stars have one or more stellar companions. As exoplanets continue to be discovered, it is crucial to examine planetary systems to identify their stellar companions. By observing a change in proper motion, companions can be detected by the acceleration they induce on their host stars. We selected 701 stars from the Hipparcos-Gaia Catalog of Accelerations (HGCA) that have existing adaptive optics imaging data gathered with Gemini/NIRI. Of these, we examined 21 stars known to host planet candidates and reduced their archival NIRI data with Gemini's DRAGONS software. We assessed these systems for companions using the NIRI images as well as Renormalized Unit Weight Error values in Gaia and accelerations in the HGCA. We detected three known visible companions and found two more systems with no visible companions but astrometric measurements indicating likely unresolved companions.