Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.stsci.edu/institute/itsd/information/streaming/archive/BeyondJWST2009/OliverGuyon032609Hi_supporting/OliverGuyon032609 Äàòà èçìåíåíèÿ: Fri Mar 27 20:13:28 2009 Äàòà èíäåêñèðîâàíèÿ: Mon Apr 6 13:59:32 2009 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: phoenix

Univ. of Arizona

Ames Research Center

Pupil mapping Exoplanet Coronagraph Observer

Pupil mapping Exoplanet Coronagraph Observer (PECO)
Olivier Guyon University of Arizona Subaru Telescope NASA JPL (architecture, technology) NASA Ames (science, technology) ITT Space Systems Division, LLC (Telescope) Lockheed Martin (Mission implementation) PECO science team

PECO


Univ. of Arizona

Ames Research Center

PECO overview

Pupil mapping Exoplanet Coronagraph Observer

High contrast coronagraphic imaging of the immediate environment of nearby stars. Characterization of planets (including Earths/SuperEarths) and dust in habitable zone

· 1.4m diameter of-axis telescope (sized for medium-class · · · ·
cost cap), 3 yr mission drift-away heliocentric orbit for maximum stability Uses high eficiency low IWA PIAA coronagraph 0.4 ­ 0.9 micron spectral coverage / R~20 Active technology development program includes NASA JPL, NASA Ames, Subaru Telescope, Lockheed Martin

PECO


Univ. of Arizona

Ames Research Center

Earth/SuperEarths with a medium-class mission ?

Yes, if: · High throughput instrument & good detector ­ high throughput coronagraph
Pupil mapping Exoplanet Coronagraph Observer

­ no photon lost, don't use dichroics instead of filters ­ combined imaging & spectroscopy ­ photon counting (no readout noise allowed) · Small Inner Working Angle AND full telescope angular resolution ­ good coronagraph ­ use blue light for discovery & orbit determination · Large amount of observation time on few targets ­ small sample of the easiest 10 to 20 targets ­ long exposure times & many revisits · Accept risk of high exozodi & low Earth frequency ­ broader science case: · exoplanetary systems architecture · extrasolar giant planets characterization · exozodi disks imaging

PECO


Univ. of Arizona

Ames Research Center

PECO uses highly eficient PIAA coronagraph (equ. x2.5 gain in tel. diam.)

Pupil mapping Exoplanet Coronagraph Observer

Utilizes lossless beam apodization with aspheric optics (mirrors or lenses) to concentrate starlight is single diffraction peak (no Airy rings). high contrast Nearly 100% throughput IWA ~2 l/d 100% search area no loss in angular resol. achromatic (with mirrors)

PECO

More info on : www.naoj.org/PIAA/

Guyon, Pluzhnik, Vanderbei, Traub, Martinache ... 2003-2006


PIAA testbed at Subaru Telescope
Univ. of Arizona Ames Research Center

Temperature-stabilized monochromatic testbed in air Uses 32x32 actuator MEMs Uses 1st generation PIAA mirrors, diamond turned Al Pupil mapping Exoplanet Coronagraph Observer

Raw image

Coherent starlight

PECO

Contrast achieved in 2 to 5 l/D zone: 2e-7 incoherent halo ghost (equivalent to exozodi) 4e-8 coherent starlight speckles (turbulence, vibrations)


Univ. of Arizona

Ames Research Center

High contrast polychromatic PIAA demonstration in preparation (NASA Ames / NASA JPL)
PIAA gen2 will be tested in JPL's High Contrast Imaging Testbed in vacuum and polychromatic light.

Pupil mapping Exoplanet Coronagraph Observer

PIAA-dedicated testbed at NASA Ames testing WFC architectures & MEMs DMs.

PECO

PIAA system scheduled to be on-sky in Dec 2009 at Subaru Telescope


Univ. of Arizona

Ames Research Center

PECO approaches theoretically optimum coronagraph performance
· High performance PIAA coronagraph ­ IWA = 2 /D

Pupil mapping Exoplanet Coronagraph Observer

­ 90% coronagraph throughput ­ No loss in telescope angular resolution: max sensitivity in background-limited case ­ Full 360 deg field probed · Simultaneous acquisition of all photons from 0.4 to 0.9 µm in 16 spectral bands, combining detection & characterization ­ High sensitivity for science and wavefront sensing ­ polarization splitting just before detector (helps with exozodi & characterization) · Wavefront control and coronagraph perform in 4 parallel channels ­ Allows scaling of IWA with lambda ­ Allows high contrast to be maintained across full wavelength coverage

PECO


Univ. of Arizona

Ames Research Center

PECO Design Reference Mission A Grand Tour of 10 nearby sun-like stars

Pupil mapping Exoplanet Coronagraph Observer

· Conduct a "Grand Tour" of ~10 nearby stars searching for small (Earth & Super-Earth) planets in their habitable zones. ­ Multiple (~10 or more) visits for detection ­ Characterization for ~5 days each to get S/N = 20-30 with ability to measure spectral features ­ exozodi distribution measurement ­ compile with other measurements (RV, Astrometry, ground imaging) · Study known RV planets, observing them at maximum elongation ­ Detect at least 12 RV planets with single visits at maximum elongation ­ Characterize at least 5 RV planets for ~2-5 days each to get S/N > 30 with ability to measure spectral features · Snapshot survey of ~100 other nearby stars to study diversity of exozodiacal disks and search for / characterize gas giant planets.

PECO


Univ. of Arizona

Ames Research Center

Number of Earths & Super Earths detected with PECO scales gracefully with aperture
# Earths, 450 nm 5 10 19 32 42 52
# Earths, 672 nm

Telescope D(m) 1.0 Pupil mapping Exoplanet Coronagraph Observer 1.2 1.4 1.6 1.8 2.0

2 5 8 14 20 30
Left: a simulation of 24 hr of PECO data showing an Earth-like planet (a=0.2) around Tau Ceti with 1 zodi of exododi dust in a uniform density disk inclined 59 degrees. This is a simulation of = 550 nm light in a 100 nm bandpass PECO (1.4-m aperture). Photon noise and 16 electrons total detector noise for an electron multiplying CCD have been added. Right: the PECO image after subtracting the right half from the left half, effectively removing the exozodiacal dust and other circularly symmetric extended emission or scattered light. The Earth-like planet is obvious as the white region on the left, and the dark region on the right is its mirror image artifact.

Earths still detectable at shorter wavelengths and smaller D
Telescope D (m) 1.0 1.2 1.4 1.6 1.8 2.0 # S-Earths, 450 nm 15 28 43 70 87 131 # S-Earths, 672 nm 5 13 20 33 44 61

· Trade study shows number of Earths detected for different telescope diameters · PECO simulation of Earth-radius planet with Earth albedo in habitable zone of candidate star · Assumes detection in < 5 attempts of < 12 hr integration · IWA of 2 lambda/D

PECO


Univ. of Arizona

Ames Research Center

PECO top 5 key technologies are identified and under study

· PIAA Coronagraph System Path to TRL6
­ ­ ­ PIAA mirror fabrication Performance demonstrations in JPL HCIT Brassboard component qualification
·

Pupil mapping Exoplanet Coronagraph Observer

Note that existing PIAA coronagraph bench is the same scale as flight components JPL HCIT Test

· Broadband Wavefront Control
­ ­ ­ ­ ­ Baseline Xinetics DM near TRL 6 MEMs DM technology in progress as potential cheaper alternative (NASA Ames Funding) Algorithms tested in HCIT LOWFS provides fine guidance, to be tested in HCIT Models predict 0.5 mas possible with existing technology (1 mas demonstrated with PIAA in the lab in air) Needed for final system verification HCIT will validate optical models SIM TOM testbed demonstrated thermo-structural

Facility

Xinetics 64x64 DM

· Pointing Control Demonstration

· Thermal-Structural-Optical modeling
­ ­ ­

· Photon-counting EMCCD Detectors

PECO

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Univ. of Arizona

Ames Research Center

Summary

Pupil mapping Exoplanet Coronagraph Observer

· PECO study shows direct imaging and characterization of Earths/ Super-Earths possible with medium-scale mission and: ­ maps exozodi down to <1 zodi sensitivity ­ extrasolar giant planets · "Conventional" telescope with off-axis mirror can be used (stability OK, wavefront quality OK). All the "magic" is in the instrument -> raising TRL for instrument is key (coronagraph, wavefront control) ­ technology development at ~$40M · PECO could launch in 2016. Total mission cost ~$810M including technology development · PECO architecture can be scaled to a flagship 3-4 m telescope without new technologies or new launch vehicles · Technology and science (exozodi) precursors to larger missions are very valuable ­ pre-PECO ? see EXCEDE poster (SMEX mission) ­ PECO -> 3-4m flagship wide field telescope with PIAA for exoplanet science

PECO