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Proceedings Paper

New design for additional sensitivity to extrasolar planet detection by stellar hallo cancellation
Author(s): Robert Content
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Paper Abstract

The proposed design includes 3 new ideas to increase the signal-noise ratio of instruments for the detection and study of extra-solar planets in space and on the ground. The instrument is to be added to systems that cancel the stellar halo, for example coronagraphs with adaptive speckle cancellation using integral field low resolution spectroscopy for speckle detection. The new design then gives an additional sensitivity to other hallo cancellation methods by hardware and/or software. The first part of the instrument spectrally splits the image into 50 to 100 narrowband images with independent optimal bandwidths and central wavelengths. This permits to have for example a uniform spectral resolution by making each bandwidth proportional to the wavelength or to adjust some bandwidths and central wavelengths to specifically target important lines. It also gives in each narrowband image optimum independent spatial sampling, for example 2 pixel per diffraction limit. This cannot be done with field sampling integral field systems as image slicers and TIGER type lens arrays. Another advantage is that there is very little contamination between spectral pixels as opposed to a slit spectrograph where the slit has a significant width compared to the pixel size, being in fact usually larger. Consequently, if a TIGER type lens array is added at the input, all 3 dimensions of the 3-D data box have very little contamination. In the second part of the instrument, the darker regions around the speckles of the narrowband images are reflected back into the spectrograph to reconstruct a white light image with a far higher contrast than at the input. The total additional gain should be equivalent to at least an order of magnitude increase in throughput. Finally, instead of reconstructing one white light image, a small number of images each with its own carefully chosen bandwidth and central wavelength can be reconstructed for specific programs as detection of life. Groups of bandwidths can also be reconstructed into white light in individual images. The system can be used as much in space than on the ground.

Paper Details

Date Published: 19 June 2006
PDF: 11 pages
Proc. SPIE 6265, Space Telescopes and Instrumentation I: Optical, Infrared, and Millimeter, 62651P (19 June 2006); doi: 10.1117/12.672237
Show Author Affiliations
Robert Content, Univ. of Durham (United Kingdom)


Published in SPIE Proceedings Vol. 6265:
Space Telescopes and Instrumentation I: Optical, Infrared, and Millimeter
John C. Mather; Howard A. MacEwen; Mattheus W. M. de Graauw, Editor(s)

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