imaging of exoplanets

New techniques, such as nulling interferometry and the use of adaptive optics coronographs, are now being developed to the stage where they are capable of directly imaging exoplanets. Already, nulling interferometry has given astronomers their first glimpse of a dust cloud around Betelgeuse, while an adaptive optics coronograph at the Palomar 1.5-meter telescope has enabled the first unambiguous identification of a brown dwarf, in the case of Gliese 229B. Direct imaging will become an increasingly important method for studying extrasolar planets. Firstly, unlike the radial velocity method, which is highly successful for discovering planets in orbits close to their host stars, imaging allows systems with larger separations (similar to those in the solar system) to be probed. Secondly, once objects have been resolved by direct imaging, it will be possible to examine their spectral features in detail and search for signs of life (see extraterrestrial life, detection). A variety of projects to image both Jupiter-like and Earthlike extrasolar worlds are under developments or planned for the future (see exoplanets, detection).