Adaptive optics (AO) imaging corrects wavefront distortions caused by turbulence in the atmosphere using deformable mirrors, allowing observations near the diffraction limit of the telescope. This enables the detection of close companions to stars that would otherwise remain unresolved, and measured contrast ratios in different passbands can be used to identify the nature of these companions.
Most AO surveys have so far concentrated on exoplanet host stars in order to study the effect of companions on the occurrence rates of planets. In collaboration with Christoph Baranec and Eric Gaidos we have launched the first dedicated campaign to detect companions to oscillating Kepler stars using AO. In particular, we are using Robo-AO at Kitt Peak Observatory in Arizona combined with 8-m class telescopes on Mauna Kea (such as Keck and Subaru) to characterize such companions. The detections will allow us to investigate the influence of companions on the oscillations of the primary star, as well as precisely measure the age of low-mass secondaries through the asteroseismic analysis of the primary star (if the stars are gravitationally bound). A paper led by IfA student Jessica Schonhut presenting the first detections has recently been submitted (see image on the right for an example), and we expect to extend this survey to a larger sample over the coming years.