Upload
ariana-pearson
View
214
Download
0
Embed Size (px)
Citation preview
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 …
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
Probing the Extrasolar Planet Diversity with
SEE COAST
SPICA MIR:Old EGPs
Direct Imaging Programs Overview
Space-based
Ground-based
1995 2000 2011 2017-20202008
SEE COASTVis/NIR: Old Jupiter+ Super Earth
Darwin/TPF-I MIR: Earth
TPF-CVis: Earth
JWSTNIR + MIR: Old EGPs
8m + XAOSPHERE / GPI / HiCIAONIR : EGPs young/massive/nearby
30/42m + XAOEPICS/ELTsNIR : EGPs intermediate Old + Super-Earth ?
>2025-30
HSTOpportunity for Space projects
In the Visible
mature giants & Super-Earths
8m + OAVLT, Keck,Gemini, Subaru
4m + OASilla, CFH
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 m) and JWST (2.5 - 28 m)
• 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
- Spectra => Chemical composition
Burrows, Sudarsky
- Rayleigh scatterring => pressure, surf. reflectivity
• Spectroscopy
Explore the Diversity
• Spectroscopy• Polarimetry- Polarization=> Clouds / albedo
Jupiter-like planet - Stam et al. 2005Earth-like planet - Stam et al. 2008
cloud
vegetation
oceanA=0
A=1
Explore the Diversity
- Spectral time variation=> variation of temperature=> surface properties
0.45 m
0.75 m
- Polarimetric time variation => surface properties
Cloud free Earth from 0.65 to 0.9 m
50° Phase angle
130°90°
• Spectroscopy• Polarimetry• Variability
Which targets ? (contrast + IWA requirements)
short wavelengths are optimal
longer wavelengths require small IWA coronagraph (2/D)
near IR (1 - 1.2 m)- self luminous planets - T > 800K
10-10 contrast required
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 m
Spectral Range 0.4 to 1.2 m
Spectral Resolution R>40
Contrast (after speckle subtraction) @ 2 /D
< 10-9
Contrast (after speckle subtraction) @ 4 /D
< 10-10
Orbit for 6 months visibility, high thermal stability
L2 Lagrangian
Hyperbolic secondary mirror 4,85 m long
Parabolic primary mirror
Two folding mirrors
Focal plane
Coronagraphy: Multi 4QPM
Baudoz et al. 2007, 08
laboratory planetContrast :6.7 10-9bandwidth 20%
Multi 4QPM : Meudon
N phase masks in series => Improves bandwidth as ^NPupil
Telescope
FQPM # 1
FQPM # 3FQPM # 2
Wavefront correction : Coherence
Speckle nullingin a limited FOV with a DM (JPL)
Summary
SEE COAST requires : • High contrast : ≈ 10-10 AND small IWA : ≈ 2 /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 ( 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)