Key Types Introduction

1
Key Types Introduction
Wesley A. Traub Harvard-Smithsonian Center for
Astrophysics

• Michelson Summer School on High-Contrast Imaging
• Caltech, Pasadena
• 20-23 July 2004

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Reminders of main topics

• C, IWA, OWA
• types
• perturbations

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C
K20 mag Bkgd objects
7 arcsec wand
J21 mag Bkgd object
20 arcsec radius circle
Ref McCarthy Zuckerman (2004) Macintosh et
al (2003)
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Search space best to date

• Keck
• IRCAL, Lick AO, K
• Ks, AO, NACO, VLTI
• WFPC2, HST, I
• CFHT, AO, H
• Keck NICMOS, 10sig
• 50 det, HST, H
• XAO, 10m, R, 2007

Airy
Halo
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Earth Jupiter-Saturn, 100 stars
Simulations by Bob Brown, STScI
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Earth Jupiter-Saturn Regions
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Radial-velocity Stars
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RV stars and brown dwarfs
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1.8-m range
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TPF-C Range
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C, IWA, OWA
Contrast C Example C 10-10 driven by
Earth/Sun 2x10-10. Inner working angle
IWA Example IWA 3 ?/D driven by 1 AU/10pc
0.100 arcsec. Outer working angle OWA
Example OWA 48 ?/D driven by N 96 actuator
DM.
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Image-plane coronagraph simulation
1st image with Airy rings
mask, centered on star image
1st pupil
2nd pupil
Lyot stop, blocks bright edges
2nd image, no star, bright planet
Ref. Pascal Borde 2004
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Wide-band (quadrant-phase) mask
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Shaped-pupil mask
y
v
x
u
Image cut along the x-axis
Pupil Spergel-Kasdin prolate-spheroidal mask
Image dark areas A(x, 0) exp(-(?x/?)2) A(0,
y) periodic messy
Kasdin, Vanderbei, Littman, Spergel, preprint,
2004
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Discrete-mapped pupil (2) Densification
Clean image, narrow FOV
Image with many aliases
Densified pupil
Entrance pupil, sparsely filled
FOV is small.
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Continuous-mapped pupil
Input wavefront uniform amplitude.
Mirror 2
100 dB 10-10 25 mag
Output wavefront prolate-spheroidal amplitude.
Output image prolate spheroid
Mirror 1
Compact star image, easily blocked
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Nulling-shearing coronagraph
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Phase ripple and speckles
Polishing errors on primary
Pupil plane
Phase ripples from primary mirror errors
Speckles generated by 3 sinusoidal components of
the polishing errors
No DM
Image plane
With DM
Image plane
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Phase amplitude ripple and speckles
h(u) ?n (anian')cos(Knu)
(bnibn')sin(Knu) total ripples Describes all
possible phase and amplitude ripples (
errors). DM can give I(?) ?(0)
?n (bn)2 (an)2
?(k?Kn) ? bigger speckles
0 0 ?(k?-Kn) ? smaller (zero)
speckles