Extrasolar Planetary Imaging Coronagraph (EPIC)

The Extrasolar Planetary Imaging Coronagraph (EPIC) is a proposed NASA Discovery mission to image and characterize extrasolar giant planets in orbits with semi-major axes between 2 and 10 AU. EPIC will provide insights into the physical nature of a variety of planets in other solar systems complimenting radial velocity (RV) and astrometric planet searches. It will detect and characterize the atmospheres of planets identified by radial velocity surveys, determine orbital inclinations and masses, characterize the atmospheres around A and F type stars which cannot be found with RV techniques, and observe the inner spatial structure and colors of debris disks. EPIC has a proposed launch date of 2012 to heliocentric Earth trailing drift-away orbit, with a 3 year mission lifetime (5 year goal), and will revisit planets at least three times at intervals of 9 months. The robust mission design is simple and flexible ensuring mission success while minimizing cost and risk. The science payload consists of a heritage optical telescope assembly (OTA), and visible nulling coronagraph (VNC) instrument. The instrument achieves a contrast ratio of 10 9 over a 4.84 arcsecond field-of-view with an unprecedented inner working angle of 0.14 arcseconds over the spectral range of 440-880 nm, with spectral resolutions from 10 – 150. The telescope is a 1.5 meter offaxis Cassegrain with an OTA wavefront error of /9, which when coupled to the VNC greatly reduces the requirements on the large scale optics, compressing them to stability requirements within the relatively compact VNC optical chain. The VNC features two integrated modular nullers, a spatial filter array (SFA), and an E2V-L3 photon counting CCD. Direct null control is accomplished from the science focal mitigating against complex wavefront and amplitude sensing and control strategies. 1.0 EPIC MISSION AND SCIENCE OVERVIEW EPIC will image and characterize extrasolar giant planets in orbits with semi-major axis between 2 and 10 AU providing insights into the physical nature of a variety of planets in other solar systems complimenting radial velocity (RV) and astrometric planet searches. EPIC will detect and characterize the atmospheres of planets identified by radial velocity surveys, determine the orbital inclinations and masses of the detected planets, characterize the atmospheres of planets around A and F type stars which cannot be found with RV techniques, observe the inner spatial structure and colors of Spitzer selected debris disks. Our discovery space is shown in Figure 1 and the EPIC spectral filter suite in Figure 2. The mission design is simple and flexible ensuring mission success while minimizing cost and risk. EPIC is proposed for a 3 year mission (5 year goal) with a launch in 2012 to a heliocentric Earth trailing drift-away orbit. Each selected planet will be visited at least 3 times at intervals of 9 months. The science payload (Figure 3) consists of a heritage optical telescope assembly (OTA) and visible nulling coronagraph (VNC) instrument. The VNC, described in more detail in section 2.0, relaxes tolerance 1 NASA/Goddard Space Flight Center, Greenbelt MD 2 Smithsonian Astrophysical Observatory, Cambridge MA 3 Johns Hopkins University, Baltimore MD 4 Space Telescope Science Institute, Baltimore MD 5 University of California Observatories/Lick Observatory 6 Carnegie Institution of Washington/DTM, Washington DC 7 Cornell University, Ithaca NY 8 NASA/Ames Research Center, Sunnyvale CA 9 Paris Observatory, Paris FR 10 NASA/Jet Propulsion Laboratory, Pasadena CA 11 University of Florida 12 Lockheed-Martin, Denver CO Space Telescopes and Instrumentation I: Optical, Infrared, and Millimeter, edited by John C. Mather, Howard A. MacEwen, Mattheus W.M. de Graauw, Proc. of SPIE Vol. 6265, 62651B, (2006) · 0277-786X/06/$15 · doi: 10.1117/12.672849 Proc. of SPIE Vol. 6265 62651B-1 C Semi-Major Axis at 10 pc (AU)