Transcript Probing the Extrasolar planet diversity with SEE-COAST

Probing the Extrasolar
Planet Diversity with
SEE COAST
ULg / CSL / LESIA / LUTH / LUAN / ETH-Zurich / IAP /
Obs. Geneva / U. Bern / UCL / ROE / U. Hertfords. /
MSSL / SRON / Astron / U. Utrecht / LAOG / ONERA /
DLR / U. Vienna / U. Nantes / U. Torino / Astrium
Pierre BAUDOZ (Paris Observatory)
A. Boccaletti, D. Mawet, J. Schneider, G. Tinetti, R. Galicher, C. Cavarroc J. Hough, P. Doel,
D. Pinfield, C.-U. Keller, J.-L. Beuzit, S. Udry, M. Ferrari, E. Martin, F. Ménard , E. Sein, &
SEE COAST Team …
Direct Imaging Programs Overview
Space-based
HST
SPICA MIR:
Old EGPs
Opportunity
for
Space
projects
SEE COAST
JWST
NIR + MIR:
Old EGPs
1995
2000
2008
4m + OA 8m + OA
Silla, CFH VLT, Keck,
Gemini, Subaru
2011
8m + XAO
SPHERE / GPI /
HiCIAO
NIR : EGPs
young/massive/ne
arby
Ground-based
Vis/NIR: Old Jupiter
In the Visible
+ Super Earth
Darwin/TPF-I
MIR: Earth
TPF-C
Vis: Earth
mature giants &
Super-Earths
2017-2020
>2025-30
30/42m + XAO
EPICS/ELTs
NIR : EGPs
intermediate
Old + Super-Earth ?
We already have targets !!!
From radial velocity surveys :
From direct imaging :
More targets to come
• We can anticipate many RV planets at longer periods (giants and tellurics)
• A few accessible from SPHERE/GPI/HiCIAO (1. - 2.3 mm) and JWST (2.5 - 28 mm)
• Motivation for exploring a different spectral range (in the visible)
 angular resolution AND contrast are required:
 A small telescope in space can be optimized for exo-planetology
 "Super Earth" as a sweet spot : brighter, earth-like notions apply (atmosphere,
climate, variations, habitability, …)
 What sort of astrophysics on these planets ?
Explore the Diversity with SEE COAST
• Spectroscopy
- Spectra =>
Chemical composition
- Rayleigh scatterring =>
pressure, surf. reflectivity
Burrows, Sudarsky
Explore the Diversity
• Spectroscopy
• Polarimetry
- Polarization
=> Clouds / albedo
Jupiter-like planet - Stam et al. 2005
Earth-like planet - Stam et al. 2008
A=0
ocean
vegetation
cloud
A=1
Explore the Diversity
• Spectroscopy
• Polarimetry
• Variability
Cloud free Earth from 0.65 to 0.9 mm
0.75 mm
- Spectral time variation
=> variation of temperature
=> surface properties
- Polarimetric time variation
=> surface properties
130°
90°0.45 mm
50° Phase angle
Which targets ?
(contrast + IWA requirements)
short wavelengths are optimal
10-10 contrast required
longer wavelengths require
small IWA coronagraph (2l/D)
near IR (1 - 1.2 mm)
- self luminous planets
- T > 800K
A proposal to Cosmic Vision …
Submitted in 2007 to ESA Cosmic Vision
✔
Parameter Value
Entrance pupil diameter
D > 1.5m
Angular resolution
70 mas @ 0.6 mm
Spectral Range
0.4 to 1.2 mm
Spectral Resolution
R>40
-9
Contrast (after
speckle mirror 4,85
< 10 m long
Hyperbolic
secondary
subtraction) @ 2 l /D
Contrast (after speckle
subtraction) @ 4 l /D
< 10-10
Orbit for 6 months visibility,
high thermal stability
L2 Lagrangian
Parabolic primary mirror
Two folding
mirrors
Focal plane
Coronagraphy: Multi 4QPM
Pupil
N phase masks in series => Improves bandwidth as ^N
Baudoz et al. 2007, 08
Multi 4QPM : Meudon
laboratory planet
bandwidth 20% Contrast :6.7 10-9
Wavefront correction : Coherence
Speckle nulling
in a limited FOV
with a DM (JPL)
Summary
SEE COAST requires :
• High contrast : ≈ 10-10
AND
small IWA : ≈ 2 l/D
SEE COAST can get :
• low res spectra of mature giants < 20pc (< 8 - 10 AU)
• colors of a few mature Super Earths < 10pc (< 4 - 5 AU)
• possibly Earths around the nearest star (a Cen)
• low res spectra of self luminous planets (extension to near IR)
SEE COAST is :
• Compatible with general astrophysics (pushing to UV, wide field ?)
• Compatible with transit spectroscopy
–
additional targets (unresolved planets) & complements IR transit characterization programs
Next steps in the project :
• refine some science cases and simulations (statistical analysis)
• elaborate optical design with industrial partners (Astrium) + derive tolerances
• technological developments in coronagraphy and wavefront control
• get prepared for next COSMIC VISION proposal (2010)