Download EPICS, exoplanet imaging with the E-ELT

EPICS, exoplanet imaging with the E-ELT
Raffaele G. Gratton,
Markus Kasper (PI), Jean-Luc Beuzit, Christophe Verinaud, Emmanuel
Aller-Carpentier, Pierre Baudoz, Anthony Boccaletti, Mariangela
Bonavita, Kjetil Dohlen,, 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, INAF-Osservatorio Astronomico di
Padova, ASTRON, ETH Zürich, University of Oxford, LAM, NOVA
Pathways, Barcelona, 16 Sep 2009
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Outline

Science goals
 Instrument and AO concept
 Science Output prediction
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Exoplanets observations 2009


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Close to 400 Exoplanets detected, >80% 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
HR 8799, Marois et al 2008
Beta Pic, Lagrange et al 2009
of HD 209458b
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2009
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Richardson et al., Nature 445, 2007
(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-lum
Planet formation
in star forming regions or young associations
Requirements:
• High spatial resolution of ~30 mas
(3 AU at 100 pc, snow line for G-star )
• Moderate contrast ~10-6
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Object Class 2, within ~20 pc
Orbit architecture, low-mass planet abundance
~500 stars from Paranal ± 30 deg, ~60-70% M-dwarfs
Requirements
• High contrasts
~10-9 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 ones
Planet evolution and atmospheres
discovered by RV, 8-m direct imaging (SPHERE, GPI) or
astrometric methods (GAIA, PRIMA)
From ESO/ESA WG report
GAIA discovery space
SPHERE discovery space
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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
1.
2.
3.
Atmospheric turbulence
Diffraction Pattern
Quasi-static instrumental
aberrations
Diff. Pol.
Visible diffraction
suppression
XAO
NIR diffraction
suppression
Coherencebased
concept?
IFS
XAO, S~90%
Diffraction + static
aberration correction
Contrast ~ 10-3-10-4
Contrast ~ 10-6
Speckle Calibration,
Differential Methods
Contrast ~ 10-9
x 1000 !
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XAO concept
Main parameters (baseline)



Serial SCAO, M4 / internal WFS, XAO
XAO: roof PWS at 825 nm, 3 kHz
200x200 actuators (20 cm pupil spacing)
Advanced RTC
algorithms
studied in parallel
to EPICS phase-A
Simulation by
Visa Korkiakoski
AO + coro
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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
Aller-Carpentier, proc. AO4ELT
100
95
90
85
SR (%)

80
75
70
65
60
55
50
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Star magnitude
10
12
HOT: XAO with APL coronagraph
Martinez et al., submitted to A&AL
 700K object next to K0 star
• Good agreement with
SPHERE simulations
• Additional gain by quasi-static
speckle calibration (SDI, ADI)
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Residual PSF calibration
From systematic PSF residuals (10-6-10-7) to 10-8-10-9
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Spectral Deconvolution (Sparks&Ford, Thatte et al.),
Trade-off: spectral bandwidth vs inner working angle,
 IFS (baseline Y-H)

Polarimetric differential imaging for smallest separation, needs
planet “feature” (e.g. CH4 band, or polarization)
 EPOL (600-900 nm)
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Coherence based methods (speckles interfere with Airy Pattern, a
planet does not)
 Self-Coherent camera (Baudoz et al, Proc. AO4ELT)
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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
-> near-pupil optics
20 nm rms in
pupil plane
20 nm rms at
10x Talbot
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End-2-end analysis
Apodizer only leads to improved final contrast
APLC
Apodizer
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Baseline Concept
All optics near the pupil plane
minimize amplitude errors and speckle irregular chromaticity
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Detection limits, incl. photon noise
G2
pc,10h
10h
G2 star,
star, 20
3pc,
Ph noise w/o spider data removal
Flat Field 10-4
Systematics
Systematics
Ph noise with spider data removal
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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 Mordasini et al. (2009)
 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, nearby+young stars
Contrast requirements
Simulations by M. Bonavita Pathways, Barcelona, 16 Sep 2009
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Predicted EPICS output
Target
class
# targets
Selfluminous
planets
Giant
planets
Neptunes
Rocky
planets
1. Young
stars
2. Nearby
stars
3. Stars
w. planets
688
~100
(~100)
Dozens
512
Dozen
~100
Dozens
Very few
(?)
Dozen
>100
Some
>100
>Dozen
>2
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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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