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Observations and modeling of Earth’s transmission spectrum through lunar eclipses: A window to transiting exoplanet characterization. E. Palle, M.R. Zapatero,

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Presentation on theme: "Observations and modeling of Earth’s transmission spectrum through lunar eclipses: A window to transiting exoplanet characterization. E. Palle, M.R. Zapatero,"— Presentation transcript:

1 Observations and modeling of Earth’s transmission spectrum through lunar eclipses: A window to transiting exoplanet characterization. E. Palle, M.R. Zapatero, P. Montañes- Rodriguez, R. Barrena, A. Garcia-Muñoz

2 Lunar eclipse August 16th 2008

3 We observed the Earth transmission spectrum during a lunar eclipse NOT, Visible, μm WHT, Near-IR, μm La Palma, Canaries

4 A penumbral eclipse seen from the Moon JAXA/NHK Moon here Lunar explorer "KAGUYA" (SELENE) on February 10, 2009

5 Umbra Penumbra Brigth Moon

6 Umbra Umbra/Bright Bright HαHα

7 Earth’s Transmission Spectrum The pale red dot Palle et al, Nature, 2009

8 Evolution of the Earth’s Transmission Spectrum during the eclipse: ZJ

9 Evolution of the Earth’s Transmission Spectrum during the eclipse: O 2 dimer band

10 Modeling efforts: Constructing a true model Non-radial symmetry Direct transmission Diffraction, refraction Diffuse light Earth – moon distance ∞ = exoplanets JAXA/NHK

11 Modeling efforts: The alpha value

12 Transmission models: Rayleigh atmosphere Garcia-Muñoz et al, in preparation

13 Transmission models: Rayleigh atmosphere Garcia-Muñoz et al, in preparation Difference

14 Transmission models: Rayleigh + Clouds (8km) + aerosols (Direct +Diffuse) Diffuse light insensitive to alpha and dominant at short wavelengths Garcia-Muñoz et al, in preparation

15 Oxygen complexes in the Earth’s atmosphere: Oxygen dimers Oxygen at visible wavelengths Intensity reversal again explained trough diffuse light contribution

16 Oxygen complexes in the Earth’s atmosphere: Oxygen dimers Oxygen at near-IR wavelengths O 2O 2 O 2N 2

17 Earth’s Reflectance Spectrum: Earthshine μmμm NOT, Visible, μm WHT, Near-IR, μm La Palma, Canaries

18 Reflected spectrumTransmission Spectrum CO 2 CH 4 O2O2 CO 2 Blue planet? O 2 O 2O 2 O 2N 2 O 2O 2 Palle et al, 2009 μmμm

19 M8 star + 1 Earth... with the E-ELT ~5 h ~ 150 h ~ 50 h ~ 25 h 20, 100, 500, 1000 spectra combined - SNR 1000 Palle et al, ApJ, submitted

20 M8 star + 1 Earth... with the E-ELT ~5 h ~ 150 h ~ 50 h ~ 25 h 20, 100, 500, 1000 spectra combined - SNR 1000 Palle et al, ApJ, submitted

21 Earth’s transmission spectrum in the mid-IR

22 More Moon Soon... VLT3 VLT1 SUBARU IRTF Palomar & HST 21st December 2010: 0.3 – 24 micron

23 Thank you

24 Still, we must pursue the characterization with direct observations Exploration of surface features  Presence of continents  Rotational period  Localized surface biomarkers (vegetation) Orbital light curve Ocean glints and polarization effects

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52 Conclusions We have obtained the Earths transmission spectra μm  First order detection and characterization of the main constituents of the Earth's atmosphere  Detection of the Ionosphere : Ca II, ( Mg, Fe, ??)  Detection of O 2 O 2 and O 2 N 2 interactions  Offers more information than the reflectance spectra We are developing models to understand the Earth’s transmission spectrum and extend this knowledge to extrasolar transiting rocky planets Using the measured Earth transmission spectrum and several stellar spectra, we compute the probability of characterizing a transiting earth with E-ELT  For a Earth in the habitability zone of an M-star, it is possible to detect H 2 O, O 2, CH 4,CO 2 (= Life) within a few tens of hours of observations.

53 Thank you

54 How deep we see in the planet atmosphere? h T(h, ) Traub, 2009 h min ? Are antropogenic signatures visible in the lower layers? Is there a surface signal?

55 Thus, the transmission spectrum of telluric planets contains more information for the atmospheric characterization than the reflected spectrum. And it is also less technically challenging But, how far are we from making the measurements ?

56 F* F* - F* ( ) + F* ( ) T A a ____ A * A p*a ______ A * + Ruido

57 Wavelength (μm) Differential transit spectroscopy M star + Earth : 1 (2) measurement S s+p / S p

58 Detection Perspectives ~5 h ~ 150 h ~ 50 h ~ 25 h Palle et al, ApJ, submitted

59 Van de Waals molecules: Weakly bound complexes They are present as minor rather than trace species. One likely origin of continuum absorption. Observed on Earth (gas) and Jupiter (gas; (H 2 ) 2 ), Ganymede, Europa and Callisto (condensed), and in the laboratory (gas/condensed). Never on Venus/Mars, where there must be CO 2 – X NOT contained in the common spectral libraries Calo and Narcisi (1980) Molecular complexes in the Earth’s atmosphere: the dimers Their total abundance is confined to the lower scale height of the atmosphere.

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61 O2O2 O3O3 Ca II H2OH2O Earth’s Transmission Spectrum Visible μmμm

62 O4O4 Ca II HαHα NO 2 ? Fraunhofer lines structure

63 CO 2 H2OH2O O 2O O 2 O 2O 2 O 2N 2 Earth’s Transmission Spectrum Near-IR ZJ μmμm

64 CH 4 CO 2 H2OH2O Earth’s Transmission Spectrum Near-IR HK μmμm

65 The Ring effect Rotational Raman Scattering (RRS) Early evidence: Sky-scattered Fraunhofer lines were less deep but broader than solar lines λ ex λ ex -Δλ, λ ex, λ ex +Δλ frequency redistribution Incident λ + Stokes + Anti-Stokes branches incident photon Incident exiting difference/ ratio

66 M8 star + 1 Earth... with the E-ELT ~5 h ~ 150 h ~ 50 h ~ 25 h Wavelength (μm) Work in progress...

67 The Ring effect: Rotational Raman scattering Transmission spectrum Solar spectrum Vountas et al. (1998)

68 Garcia-Muñoz et al, in preparation

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70 Reflection vs Transmission

71 How deep we see in the planet atmosphere? Evidences? Ref.: Kaltenegger & Traub 2009

72 The Earthshine on the moon ES/MS = albedo (+ geometry and moon properties)

73 Chappuis Ozone band B-O 2 A-O 2 Atmospheric Water vapor Rayleigh Scattering Spectral Albedo of the Earth: 2003/11/19 Montañés-Rodriguez et al., ApJ, 2006

74 Kaltenegger & Traub Palle et al, 2009

75 Terrestrial inner-orbit planets based on their transits: - About 50 planets if most have R ~ 1.0 Re - About 185 planets if most have R ~ 1.3 Re - About 640 planets if most have R ~ 2.2 Re (Or possibly some combination of the above) About 12% of the cases with two or more planets per system CoRoT & KEPLER can provide this input Many other surveys: Plato, TESS, Ground-based searches,...

76 TEST

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