Comparison of Imaging Approaches for Extrasolar Planet Detection

We have been examining the optical performance requirements of systems capable of directly detecting Jupiter-like and Earth-like planets around nearby stars. The system requirements are driven by (1) the desire to observe a statistically significant stellar population, such that even a null result would have scientific value, (2) the extreme brightness contrast between the parent stars and their companions, and (3) the required sensitivity owing to the intrinsically faint planetary signals. By using detection and characterization of Earth-like planets as our ultimate objective, we plan to establish a technological target which can then be used to govern near-term developmental activities, including system designs to search for larger, brighter planets around the nearest stars. Since we have no a priori information as to how many planets may exist around a given star, imaging is deemed to provide the most robust method of searching. There are two methods of producing images: directly and interferometrically, and three wavelength regions to be considered: visible, infrared, and submillimeter. Our study includes this entire matrix of possible approaches.