EPICS, exoplanet imaging with the EELT

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EPICS, exoplanet imaging with the E-ELT

• Markus Kasper, Jean-Luc Beuzit, Christophe
  Verinaud, Emmanuel Aller-Carpentier, Pierre
  Baudoz, Anthony Boccaletti, Mariangela Bonavita,
  Kjetil Dohlen, Raffaele G. Gratton, Norbert
  Hubin, Florian Kerber, Visa Korkiaskoski, Patrice
  Martinez, Patrick Rabou, Ronald Roelfsema, Hans
  Martin Schmid, Niranjan Thatte, Lars Venema,
  Natalia Yaitskova
• ESO, LAOG, LESIA, FIZEAU, Osservatorio
  Astronomico di Padova, ASTRON, ETH Zürich,
  University of Oxford, LAM, NOVA

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Outline

• Science goals (6s)
• Instrument and AO concept (12s)
• Science Output prediction (4s)

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Exoplanets observations early 2009

• 300 Exoplanets detected, gt80 by radial
  velocities, mostly gas giants, a dozen Neptunes
  and a handful of Super-Earths

• Constraints on Mass function, orbit distribution,
  metallicity
• Some spectral information from transiting planets

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(Some) open issues

• Planet formation (core accretion vs gravitational
  disk instability)
• Planet evolution (accretion shock vs spherical
  contraction / hot start)
• Orbit architecture (Where do planets form?, role
  of migration and scattering)
• Abundance of low-mass and rocky planets
• Giant planet atmospheres

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Object Class 1, young self-lumPlanet formation
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Object Class 2, within 20 pcOrbit architecture,
low-mass planet abundance
500 stars from Paranal 30 deg, 60-70
M-dwarfs

• Requirements
• High contrasts10-9 at 250 mas (Jupiter at
  20pc)
• spatial resolution 10-8 at 40 mas (Gl
  581d,8 M?)

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Object Class 3, already known onesPlanet
evolution and atmospheres

• discovered by RV, 8-m direct imaging (SPHERE,
  GPI) or astrometric methods (GAIA, PRIMA)

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Contrast requirements summary
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Concept
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Concept Achieve very high contrast

• Highest contrast observations require multiple
  correction stages to correct for
• Atmospheric turbulence
• Diffraction Pattern
• Quasi-static instrumental aberrations

NIR diffraction suppression
x 1000 !
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XAO concept

• Main parameters (baseline)
• Serial SCAOM4 / internal WFS, XAO
• XAO roof PWS at 825 nm, 3 kHz
• 200x200 actuators (20 cm pupil spacing)

AO coro
1e-6
1e-7
RTC requirementsEfficient algorithms studied
outside EPICS phase-A
Numerical simulation, see poster of Visa
Korkiakoski
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High Order Testbench (HOT)Demonstrate XAO / high
contrast concepts

• Developed at ESO in collaboration with Arcetri
  and Durham Univ.
• Turb. simulator, 32x32 DM, SHS, PWS,
  coronagraphy, NIR camera
• H-band Strehl ratios 90 in 0.5? seeing (SPIE
  2008, Esposito et al. Aller-Carpentier et al. )
  correcting 8-m aperture for 600 modes

See poster of Aller-Carpentier
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HOT XAO with APL coronagraph

• Good agreement with SPHERE simulations
• Additional gain by quasi-static speckle
  calibration (SDI, ADI)

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HOT speckle stability
0 6hrs 30 hrs
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Correction of quasi-static WFE incl. segments
piston

• DM cleans its control area from speckles
• Need measure static aberrations some nm level at
  science wavelength through residual turbulence
  (PD or Speckle Nulling)

Standard WFE specs ok for most optics (near pupil)
Concept to be demonstrated ? FP7 funded exp.
(FFREE_at_LAOG and HOT)
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HOT Segments piston and correction of
quasi-static WFE
HOT pupil with DM and segmentation
With segmentation
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Residual PSF calibration

• Getting from systematic PSF residuals (10-6-10-7)
  to 10-8-10-9
• Spectral Devonvolution (SparksFord, Thatte et
  al.), Trade-off spectral bandwidth vs inner
  working angle,? IFS (baseline Y-H)
• Multi-band spectral or polarimetric differential
  imaging for smallest separation, needs planet
  feature (e.g. CH4 band, or polarization)? IFS
  and differential polarimeter (600-900 nm)
• Coherence based methods (speckles interfere with
  Airy Pattern, a planet does not) ? Self-Coherent
  camera (see talk by P. Baudoz)
• Angular Differential Imaging (ADI) ? All

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Example Spectral Deconvolution
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Speckle chromaticity and Fresnel
SD needs smooth speckle spectrum -gt near-pupil
optics
20 nm rms at 10x Talbot
20 nm rms in pupil plane
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End-2-end analysis

• Apodizer only leads to improved final contrast

APLC
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E-ELT WFE requirements

• Segment alignment (PTT) lt 36 nm rms
• Segment figuring lt 50 nm rms
• Segment high orders lt 50 nm rms
• M2-5, fgt50 cycles/pupil lt 30 nm rms
• Roughness lt 5 nm rms

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Baseline Concept
All optics near the pupil planeminimize
amplitude errors and speckle irregular
chromaticity
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Detection rates, MC simulation
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Predicted Science Output

• MC simulations
• planet population with orbit and mass
  distribution from e.g. Mordasini (2007)
• Model planet brightness (thermal, reflected,
  albedo, phase angle,)
• Match statistics with RV results

• Contrast model
• Analytical AO model incl. realistic error budget
• Spectral deconvolution
• No diffraction or static WFE
• Y-H, 10 throughput, 4h obs

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Detection rates, nearbyyoung stars
Contrast requirements
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Predicted EPICS output
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Summary

• EPICS is the NIR E-ELT instrument for Exoplanet
  research
• Phase-A to study concept, demonstrate feasibility
  by prototyping, provide feedback to E-ELT and
  come up with a development plan
• Conclusion of Phase-A early 2010
• Exploits E-ELT capabilities (spatial resolution
  and collecting power) in order to greatly advance
  Exoplanet research (discovery and
  characterization)

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END
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