Transcript O 3 - ESEP

Planetary
Characterization
Giovanna Tinetti
University College London
- France Allard (CRAL, radiative transfer, spectral models)
- Nicole Allard (GEPI, spectroscopy of atomic species)
- Alan Aylward et al. (UCL, 3D upper atm. modeling)
- Bruno Bezard (LESIA, solar system, models/observations)
- James Cho (QMUL, atmosphere dynamics)
- Athena Coustenis (LESIA, solar system, models/obs.)
- Olivier Grasset (Un. Nantes, planetary interior)
- John Harries (Imperial College, Earth mod/obs)
- Hugh Jones (Un. of Herthfordshire, exoplanet obs.)
- Helmut Lammer (IWF/OeAW, upper atm.)
- Emmanuel Lellouch (LESIA, solar system, model/obs.)
- Enric Palle (IAC, Earth observations/biosig.)
- Heike Rauer et al. (DLR, atmos/biosig. modeling)
- Jean Schneider (LUTH, exoplanet observations)
- Franck Selsis (Un. Bordeaux, planetary models/biosig.)
- Daphne Stam (SRON, exoplanet polarization)
- Jonathan Tennyson (UCL, spectroscopy of molecules)
- Giovanna Tinetti (UCL, exoplanet spectral simulations)
- Yuk Yung (Caltech, photochemistry/rad. transfer)
Projects
Spectral
Bands
Output
Type of Planets
High Accuracy RV
Visible/N IR
Mass, address, statistics
Giant and super-Earths
Cold Spitzer
MIR
Photometry and low res.
spectroscopy of transiting
planets
Nearby Ho t Jupiters and
Neptune s, Super-Earths
around M stars?
Warm Spitzer
MIR
Photometry at 3.6 and 4.5
micron
Nearby Ho t Jupiters and
Neptune s, Super-Earths
around M stars?
HS T
(UV ) VIS, NIR
Low, Mediu m, (High ) res.
Spectroscopy for transiting
planets
Nearby Ho t Jupiters and
Neptune s, Super-Earths
around M-stars?
SPHER E/GPI (2011)
NIR
Photometry & spectra
Young/massiv e nearby giants
VIS
Photometry , polarization
Young/massiv e nearby giants
NIR-MIR
Photometry &
Down to Super-Earths &
favourable Earth-size Planets;
Habitabl e zone M-stars
JWST (2013)
High Res. Spectroscopy
transiting planets
SPICA (2018)
(NIR)-MIRFIR
Low & High Res.
Spectroscopy transiting
planets
Down to Super-Earths &
favourable Earth-size Planets;
Habitabl e zone M-stars
ELTs (2018-2020)
VIS-NIR
Spectroscopy, Photometry,
Polarizatio n
Matur e giants, super-Earths
Small/ medium tele scope
+ Coronograph
VIS + (NIR)
(SEE-Coast, SPICAcoronograph , Epic, Peco,
Access etc.)
MIR
Photometry & spectra &
degree of polari zation
Matur e giants, nearby superEarths
Photometry & Spectra
Astrometry / RV with
ELT
Visible
Mass, address, statistics
Earth sized pla nets, habitable
zone
TPF-C
VIS (NIR)
Low-Medi um Res.
Spectroscopy ~ 100
Down to Earth sized planets
in habitable zone
TPF-O
VIS (NIR)
Mediu m Res. Spectroscopy
300-1000
Down to Earth sized planets
in habitable zone
TPF-I/Darwin
MIR
Low-Res. Spectroscopy < 40
Down to Earth sized planets
in habitable zone
Atmospheric characterisation: priorities for
future missions
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Spectroscopy!
Spectral resolution
Signal to noise reachable
Integration time
Wavelength range
Instrument sensitivity
Redundancies to address degeneracy
Variety of planetary types (Gas-giants, Neptunes,
Terrestrial Planets, orbiting different types of stars, @
different orbital separation
• Type of targets reachable
dnv
kav
2008
Contribution: advanced.
Low res; spectroscopy from space.
Higher res. from ground?
Hot planets orbiting very close in,
Targets down to Super-Earth
UV-IR
~2015-2018
JWST, SPICA:
High spectral res. from space,
down to ~Earth-size,
planets orbiting close-in,
Habitable zone M-stars?
IR
Further into the future:
Improved resolution, sensitivity,
broader spectral window etc.
2008
Contribution: study phase.
2010: VLT-Sphere first light
(warm Jupiters, large separation)
~2015-2018
Small size space-based missions?
E-ELT-EPICS (ground)
Low spectral res. ~ 65,
planets with larger separation,
down to Super-Earth size,
Habitable zone
VIS-NIR-MIR
Further into the future:
Large space-based missions,
Planets down to Earth-size,
Habitable zone
Higher spect. resolution
Transiting planets
The present
(Hubble, Spitzer, ground)
Planets orbiting VERY close in +
Photometry/low spectral resolution from
space, very high spect. res from ground?
Hot Jupiters, hot Neptunes,
hot-Super Earths?
Radial velocity / Occultation
HD 209458b
Period = 3.524738 days
Mass = 0.69 ±0.05 MJupiter
Radius = 1.35 ±0.04 RJupiter
Density = 0.35 ±0.05 g/cm3
Radius/mass ratio
Ice
Silicate
Carbon
Sotin, Grasset & Mocquet;
Kuchner & Seager;
First atmospheric component: Na
0.0232±0.0057%
Charbonneau et al., 2002
Sensitive to overall temperature,
main atmospheric component, planetary mass
Light curves of a non-transtiting exoplanet
υ Andromeda
light-curve @ 24 μm
contribution from
the planet:
~0.1%
Harrington et al., Science, 2006
VIS-MIR transit spectroscopy
Knutson et al., 2008
Pont et al., 2007
Deming et al., 2007
Charbonneau et al., 2008
Beaulieu et al., 2008
Swain et al., 2008
Knutson et al., 2008
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Swain et al., 2008a
Swain et al., 2008a +
Grillmair, 2007
Swain, Vasisht, Tinetti, Bouwman, Deming, Nature, submitted
H2O, CH4, CO + other C-N bearing molecules
The short term future
(JWST, SPICA?)
Planets orbiting VERY close in +
High spectral resolution from space
Hot Jupiters, hot Neptunes,
hot-Super Earths,
hot Earth-size?
Warm Earth-size (Mstar)
James Webb Space Telescope
performances (MIRI)
Earth-size Planets @ 10, 20, 30 parsec
Cavarroc, Cornia, Tinetti, Boccaletti, 2008
SPICA
• Japanese (ISAS/JAXA) proposal for
successor mission to Spitzer, Akari and
Herschel
• Telescope: 3.5m, <5 K
– Herschel: 3.5m, 80K
– JWST: ~6m, ~45K
• Core λ: 5-200 μm
– Δθ=0.35”-14”
• Orbit: Sun-Earth L2 Halo
• Warm Launch, Cooling in Orbit
– No Cryogen → 3.2 t
– Long Lifetime
• Launch: 2017
Primary and secondary transit
photometry/spectroscpy have been
shown to be very powerful diagnostic
techniques to probe the atmospheres
of extrasolar planets.
But for planets with larger separation
from the Star…
Direct detection
Stellar light reflected by the planet
(UV/visible)
g
Molecules/clouds/surface types
Multiple scattering of reflected photons:
Rayleigh scattering/clouds/surface types
Molecules with electronic transitions
Photons emitted by the
planet
(IR)
Molecules/thermal structure
g
Photons emitted by the planet,
Molecules (roto-vibrational modes),
thermal structure, clouds
O3
In the visible, sunlight is
reflected and scattered back to
the observer, and is absorbed by
materials on the planet’s surface
and in its atmosphere.
Net
60
Stratopause
50
The planet is warm and
gives off its own infrared
radiation. As this radiation
escapes to space, materials
in the atmosphere absorb it
and produce spectral
features.
Emission
40
Ozone
Absorption
30
20
Tropopause
10
Absorption
Water Vapor
0
200
250
300
VIS - Near IR
Molecules in 0.4-2.5 microns
Molecule Absorption bands (μm)
H2O
0.51, 0.57, 0.61, 0.65, 0.72, 0.82, 0.94, 1.13, 1.41, 1.88, 2.6
CH4
0.48, 0.54, 0.57. 0.6, 0.67, 0.7, 0.79, 0.84, 0.86, 0.73, 0.89, 1.69,
2.3
CO2
1.21, 1.57, 1.6. 2.03
NH3
0.55, 0.65, 0.93, 1.5, 2, 2.3
O3
0.45-0.75 (the Chappuis band)
O2
0.58, 0.69, 0.76, 1.27
CO
1.2, 1.7, 2.4
H 2S
VIS: Albedo
H2O, CH4, NH3, C2H6, CO, H2S, CO2 …
Karkoschka, Icarus, 1998
Terrestrial Planet
Spectra Vary
Widely
in Solar System
VIS-Near-IR
signatures
for
terrestrial
planets
in our Solar System
?
CO2
CO2
VENUS
X 0.60
EARTH-CIRRUS
O2
O3
H2O
H2O
H2O
O2
H2O
MARS
Iron
oxides
H2O ice
EARTH-OCEAN
Polarization: a huge help to
distinguish clouds
Polarization
variations 10%-40%
(Stam et al 2004)
=> Starlight is NOT
polarized
Polarization: sensitivity to phase
Polarization
variations 10%-40%
(Stam et al 2004)
=> Starlight is NOT
polarized
IR
Molecules in the Mid-IR
H2O, CO2, CH4, Hydrocarbons, HCN,
H2S, SO2, CO, N2O, NH3 ….
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Terrestrial
Planet Spectra
Widely in Solar
System
MIR
signatures
forVary
terrestrial
planets
in our Solar System
IR: Thermal structure, dynamics
Knutson et al., Nature, 2007; ApJ, 2008
ESO Extremely Large Telescope-EPICS
EPICS is an instrument project for the direct imaging and
characterization of extra-solar planets with the
European ELT
• The eXtremeAdaptive Optics(XAO) system
- The Diffraction Suppression System(or coronagraph)
- The Speckle Suppression System
• The Scientific Instrument(s)
- Integral Field Spectroscopy
- Differential Polarimetry
- A speckle coherence-based instrument
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Missions concepts considered
for studies (US)
Access: coronagraphs for exoplanet missions (John Trauger)
Davinci, Dilute Aperture VIsible Nulling Coron. Imager(Michael Shao)
EPIC: directly imaging exoplanets orbiting nearby stars (Mark Clampin)
PECO: refining a Phase Induced Amplitude Apodization Coronograph (Olivier
Guyon)
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M-mission from space or first generation from
ground
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The New World Observer
NWO is a large-class Exoplanet mission that employs two
spacecrafts: a “starshade” to suppress starlight before it enters
the telescope and a conventional telescope to detect and
characterize exo-planets.
Cash, Nature, 2006
Spectroscopy
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H2O
O2
CH4
NH3
S. Seager
Coronagraph on SPICA
• Assumed observation mode
- imaging and low res. spectroscopy
- because of limit of sensitivity
• Distance/number of target
- a few hundred of target in 10pc
- a few x 10 seems too small
- a few x 1000 is difficult to complete survey
• Wavelength
- 3.5-27um rather than 5-27um to detect excess in
spectral, and advantage on IWA.
• IWA
- limited by coronagraph method.
- 3.3 lambda/D (binary mask mode, baseline of SPICA
coronagrah)
- 1.2-1.5 lambda/D (PIAA mode)
• Contrast
- finally 10^-7. To obtain it, 10^-6 for raw contrast.
(~10 is assumed as gain of subtraction)
Enya et al., 2008
Direct Detection
of Earth-size Planets IR