Imaging the Surfaces of Stars
Under even the best atmospheric conditions, telescope diffraction fundamentally limits the angular resolution for astronomical imaging. Using interferometry (Go, Michelson!), we can coherently combine light from widely-separated telescopes to overcome the single-telescope diffraction limit to boost our imaging resolution by orders of magnitude. I will review recent technical and scientific breakthroughs made possible by the Michigan Infrared Combiner of the CHARA Array on Mt. Wilson, CA, with baselines of 330 meters allowing near-infrared imaging with sub-milli-arcsecond resolution. I will present the first resolved images of main sequence stars besides the Sun, focusing on the oblate and gravity-darkened photospheres of rapidly rotating stars. We can now also resolve the interacting components of close binary stars for the first time, image magnetic spots on active stars, and watch novae explode in realtime. Taking advantage of recent breakthroughs in infrared detectors, we hope to soon image the inner regions of planet-forming disks around very young stars.