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Laboratory data and modeling of Plutos spectra Laboratoire de Planétologie de Grenoble, CNRS - Université J. Fourier

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Presentation on theme: "Laboratory data and modeling of Plutos spectra Laboratoire de Planétologie de Grenoble, CNRS - Université J. Fourier"— Presentation transcript:

1 Laboratory data and modeling of Plutos spectra Laboratoire de Planétologie de Grenoble, CNRS - Université J. Fourier Bernard Schmitt Eric Quirico, Sylvain Douté et Olivier Brissaud

2 Optical properties of ices Schmitt et al., 1998, Solar System Ices, p.199

3 Mesurement of spectral properties (0,4 – 200 µm) of molecular solids Study effects of: - Temperature - Phases - Composition - Compounds - UV irradiations Infrared Spectrometer with an optical cryogenic system ( K) Solids : - Ices - Clathrates, Hydrates, - Organics, - Minerals, …

4 Ices, organics, … Near and mid-infrared

5 Nitrogen 2 phases Transition : 35.6K - 2 very weak bands - Very sensitive to phase - Sensitive to temperature - Fundamental band sensitive to CO 2, H 2 O - Spectral shape surface thermometer Grundy et al., 1993, Icarus, 105, 254 Schmitt et al., 1998, Solar System Ices, 199

6 Methane Grundy et al., 2002, Icarus, 155, 486 -Very large number of bands of various intensities, down to the visible range - Band shape sensitive to temperature Vis Near-IR Mid-IR

7 Methane

8 CH 4 – N 2 mixtures Schmitt et al., 1998, Solar System Ices, Spectra very sensitive on the way the molecular mixture is formed - Crystal growth from the liquid under thermodynamic equilibrium best represent the surface of Pluton and Triton !

9 Diluted CH 4 – N 2 mixtures CH 4 spectrum sensitive to : - Pure vs diluted - N 2 phase and temperature - CH 4 abundance (> 2%) Quirico & Schmitt 1997a Icarus, 127, 354

10 Schmitt et al., 1998, Solar System Ices, 199 Spectrum = combination of the spectra of the saturated N 2 :CH 4 solutions Rich CH 4 – N 2 mixtures Quirico et al; 1996 PSS, 44, 973

11 Water ice Schmitt et al., 1998, Solar System Ices, 199 Amorphous phase : Spectrum slightly depend on temperature - Similar to high temperature crystalline Crystalline phase : Strong dependence with temperature, 1.65 µm band H 2 O ice thermometer

12 Water ice : Phase and temperature Grundy et al., 1998, JGR E, 103, 25809

13 Ammonia Schmitt et al., 1998, Solar System Ices, 199 Pure ammonia : - Several phases Ammonia hydrates: - 3 hydrate types + several phases Complex spectra and not yet well studied (in course …)

14 Simple hydrocarbons Quirico & Schmitt 1997a Icarus, 127, 354

15 Carbon monoxyde Quirico & Schmitt 1997a Icarus, 127, 354 Quirico & Schmitt 1997a Icarus, 128, 181

16 Carbon dioxyde Quirico & Schmitt 1997a Icarus, 127, Weakly sensitive to temperature

17 Methanol, nitriles, oxydes, … Many molecules measured or under study : CH 3 OH, HC 3 N, C 3 H 4, C 2 H 5 CN, C 6 H 6, C 3 N 3 H 3, …

18 Mesure de la réflectance spectrale (0,3 – 4,8 µm) bidirectionnelle des surfaces granulaires Etude effets de la : - Composition, - Taille et forme des grains, - Rugosité de surface, - Indices optiques, … Mesure spectres et fonctions de diffusion : - Glaces, minéraux, - Organiques, - Matériaux géophysiques, Applications : Spectro-imagerie spatiale

19 Visible slope and near-IR band strength sensitive to composition and structure of the macromolecular solid yellow tholins poly-HCN black tholins samples from LISA C-H-N compounds Wavelength (nm) Reflectance Bernard et al. 2006, Icarus 185, 301

20 surfaces par spectro-imagerie Composition – Identification de molécules – Etat physique – Modes de coexistence – Abondances – Distribution spatiale – Variations temporelles Origine - Evolutions – Origine chimique des molécules –Complexité de la matière organique – Microphysique échanges surface/atmosphère – Transports (cycles jour, saison, climat, …) – Liens avec géologie, topographie, …

21 Molecules identification Quirico et al Icarus, 139, 159

22 Physical state Quirico et al Icarus, 139, 159

23 Distribution, abundance, grain size Different ways of mixing : - Molecular - Compounds - Granular - Spatial - Stratigraphy (tholins) Douté et al Icarus, 142, 421

24 Complete modeling Comparison between objects

25 New-Horizon : spatial distribution Quirico et al Icarus, 139, 159


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