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Proceedings Paper

Planetary system and star formation science with non-redundant masking on JWST
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Paper Abstract

Non-redundant masking (NRM) is a high contrast high resolution technique that is relevant for future space missions dedicated to either general astrophysics or extrasolar planetary astronomy. On the ground NRM has opened a rich target space between 0.5 to 4 resolution elements from bright stars. It enabled moderate contrast very high angular resolution observations that have provided dynamical masses for targets beyond the resolution of the Hubble Space Telescope. Such observations challenge the best models of ultra-cool dwarf stars' atmospheres and interiors. The technique succeeds because it sidesteps the effects of speckle noise that plagues direct imaging at moderate Strehl ratios. On a space telescope NRM mitigates instrument-induced speckle noise, thus enabling high contrast even when images are barely diffraction-limited. The non-redundant mask in the Fine Guidance Sensor Tunable Filter Imager (FGS-TFI) on the James Webb Space Telescope (JWST) will open up a search space between 50 and 400 mas at wavelengths longer than 3.8μm. We present simulations that estimate achievable contrast on JWST, and report preliminary results of a testbed experiment using a mask with the same geometry as JWST's. We expect contrast of the order of 104 will be achievable in a 10 ks exposure of an M = 7 star, with observing, target acquisition, and data calibration methods common to the three other imaging instruments on board JWST. As an example of the potential science possible with NRM, we show that if a planet were responsible for clearing the inner 5 AU of the disk around HR8799, it would likely be detectable using JWST FGS-TFI's NRM at 4.6 microns. Stars as bright as M = 3 will also be observable with JWST's NRM, meshing well with next-generation ground-based extreme adaptive optics coronagraphs. JWST NRM's parameter space is inaccessible to both JWST coronagraphs and future 30-m class ground-based telescopes, especially in the mid-IR.

Paper Details

Date Published: 11 August 2010
PDF: 13 pages
Proc. SPIE 7731, Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave, 77313W (11 August 2010); doi: 10.1117/12.858161
Show Author Affiliations
Anand Sivaramakrishnan, American Museum of Natural History (United States)
David Lafrenière, Univ. de Montréal (Canada)
Peter G. Tuthill, The Univ. of Sydney (Australia)
Michael J. Ireland, The Univ. of Sydney (Australia)
James P. Lloyd, Cornell Univ. (United States)
Frantz Martinache, Subaru Telescope, National Astronomical Observatory of Japan (United States)
Russell B. Makidon, Space Telescope Science Institute (United States)
Rémi Soummer, Space Telescope Science Institute (United States)
René Doyon, Univ. de Montréal (Canada)
Mathilde Beaulieu, Univ. de Montréal (Canada)
Sébastien Parmentier, Stony Brook Univ. (United States)
Charles A. Beichman, NASA ExoPlanet Science Institute, California Institute of Technology (United States)

Published in SPIE Proceedings Vol. 7731:
Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave
Jacobus M. Oschmann Jr.; Mark C. Clampin; Howard A. MacEwen, Editor(s)

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