Planetary Characterization

1. Planetary Characterization Giovanna Tinetti University College London

2. - 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)

4. Atmospheric characterisation: priorities for future missions • 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

5. dnvkav 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 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.

6. Transiting planets

7. 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?

8. 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

9. Radius/mass ratio Ice Silicate Carbon Sotin, Grasset & Mocquet; Kuchner & Seager;

10. 0.0232±0.0057% First atmospheric component: Na Charbonneau et al., 2002

11. Sensitive to overall temperature, main atmospheric component, planetary mass

12. Light curves of a non-transtiting exoplanet υAndromeda light-curve @ 24 μmcontribution from the planet: ~0.1% Harrington et al., Science, 2006

13. d 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 Swain et al., 2008a + Grillmair, 2007 Swain et al., 2008a Swain, Vasisht, Tinetti, Bouwman, Deming, Nature, submitted H2O, CH4, CO + other C-N bearing molecules

14. 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)

15. James Webb Space Telescope performances (MIRI) Earth-size Planets @ 10, 20, 30 parsec Cavarroc, Cornia, Tinetti,Boccaletti, 2008

16. 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

17. 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…

18. Direct detection

19. g g Stellar light reflected by the planet (UV/visible) Photons emitted by the planet (IR) Molecules/thermal structure Molecules/clouds/surface types Multiple scattering of reflected photons: Rayleigh scattering/clouds/surface types Molecules with electronic transitions Photons emitted by the planet, Molecules (roto-vibrational modes), thermal structure, clouds

20. Net 60 Stratopause 50 Emission 40 Ozone Absorption 30 20 Tropopause 10 Absorption Water Vapor 0 200 250 300 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. O3 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.

21. VIS - Near IR

22. Molecules in 0.4-2.5 microns

23. H2O, CH4, NH3, C2H6, CO, H2S, CO2 … VIS: Albedo Karkoschka, Icarus, 1998

24. ? VENUS X 0.60 CO2 CO2 EARTH-CIRRUS O2 H2O H2O O2 O3 H2O H2O MARS Iron oxides H2O ice EARTH-OCEAN VIS-Near-IR signatures for terrestrial planets in our Solar System Terrestrial Planet Spectra Vary Widely in Solar System

25. Polarization: a huge help to distinguish clouds • Polarization variations 10%-40% (Stam et al 2004) => Starlight is NOT polarized

26. Polarization: sensitivity to phase • Polarization variations 10%-40% (Stam et al 2004) => Starlight is NOT polarized

27. IR

28. Molecules in the Mid-IR H2O, CO2, CH4, Hydrocarbons, HCN, H2S, SO2, CO, N2O, NH3 ….

29. MIR signatures for terrestrial planets in our Solar System Terrestrial Planet Spectra Vary Widely in Solar System

30. IR: Thermal structure, dynamics Knutson et al., Nature, 2007; ApJ, 2008

31. 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

32. 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)

33. M-mission from space or first generation from ground

34. 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

36. H2O O2 Spectroscopy CH4 NH3 S. Seager

37. 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

38. Direct Detection of Earth-size Planets IR