Imaging Exoplanets: From Adaptive Optics to Starshades In Space
Direct imaging of exoplanets – “seeing” the planet as a separate point of light near a star - is extremely difficult, and several decades ago, scientists used to say that it would be impossible to image Earth-like exoplanets. Today this seems possible, using some combination of adaptive optics technology, coronagraphs, or starshades. Adaptive lets telescopes on the ground compensate for the Earth’s atmosphere. Coronagraphs use ultraprecise masks inside telescopes to block the diffracted light from a bright star. Starshades combine a space telescope with a huge flower-shaped spacecraft that flies in formation to block the starlight before it even reaches the So what are we waiting for? What are the technical challenges associated with developing an exoplanet-hunting space telescopes? The future NASA Wide-Field Infrared Survey telescope could test out some of these technologies by studying Jupiter-like planets, and the proposed Habitable Planets Explorer (HabEX) mission could fully integrate them in a search for earthlike planets around dozens of nearby stars.