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Laboratory Spectroscopy in Herschel/PACS Range of Astrophysically Important Minerals

Explore physical characterization and spectral signatures of astro-relevant minerals at AAS meeting. Study covers minerals from meteorites, planets, and astronomical spectroscopy. Get insights into minerals' absorption coefficients, species dependence, and temperature effects for the PACS range. Funding by NASA-JPL.

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Laboratory Spectroscopy in Herschel/PACS Range of Astrophysically Important Minerals

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  1. Presented at AAS meeting, Washington DC Jan 2010 Laboratory Spectroscopy in Herschel/PACS Range of Astrophysically Important Minerals Tatiana Brusentsova, Doug Maukonen, Pedro Figueiredo, Himanshu Saxena, Robert E. Peale Andy Nissinboim, Joseph Boesenberg, Julie Leibold, Kristen Sherman George E. Harlow , Denton Ebel Karl Hibbitts and Carey Lisse

  2. Astro-relevant minerals high-T (>1000K) predictions from condensation calculations minerals found in carbonaceous chondrite meteorites minerals interpreted from Spitzer/Deep Impact spectrum, found in Stardust samples and in IDPs minerals found in differentiated meteorites and planets minerals reported in astronomical spectroscopy

  3. Lab measurements support PACS data analysis Thermal emission: 4 p c k(w) e0(w) dw • e0(w) = Planck function • k = (S/m) ln (1/T) = mass absorption coef. • S = sample cross-section • m = mass in sample • T = transmittance spectrum

  4. Physical Characterization Select grains from AMNH mineral collection • Crush to separate intergrowths • Sweep magnetic impurities • Dissolve carbonate impurities in HCl (acid) • Hand pick clean grains Verify crystallography (single crystal x-ray) Electron microprobe on single grains • Chemical composition • Cation stoichiometry

  5. Pellet preparation and spectroscopy cerussite Make dust • micronizing mill • Stokes settling • grain size distribution Weigh and mix in polyethylene powder Melt press to pellets Fourier transform spectrometer: 14-250 microns 20 microns

  6. Disseminate results • Planetary Data System, Cross-referenced • Curation of all samples at AMNH • Samples • Pellets • All data

  7. Carbonates: Calcite & Dolomite group Spitzer PACS Spitzer PACS • The lines in the PACS • range within the same • mineral group directly • depend on the mineral • species

  8. Hydroxyl-containing, acid- and hydrated Carbonates: Spitzer PACS Spitzer PACS

  9. Phyllosilicates (micas) PACS

  10. Spitzer Spitzer PACS PACS Feldspars both Plagioclase- (Albite-Anorthite) and Alkali- (Albite-Orthoclase) solid solution series were examined

  11. Sulfides: PACS

  12. The effect of smaller particle size: • The increase of mass absorption coefficient values for the samples with • smaller mean particle size

  13. Temperature dependence Icy dust

  14. 150 Minerals Sampled • Nesosilicates: Olivines, Garnets, Phenakites • Silica minerals • Inosilicates: Pyroxenes (Clino- and Ortho-), “Pyroxenoids” • Feldspars: Alkali and Plagioclase • Double-chain silicates: Amphiboles (Orthorhombic, Calcic clino-) • Cyclosilicates • Carbonates: Calcites, Aragonites, Dolomites, hydroxylated, Hydrated-normal, acid • Phyllosilicates: Smectites, Chlorites, Micas, Kaolinites, Serpentines, Talcs • Sorosilicates • Oxides • Sulfides

  15. Applications • Early PACS report: 69 mm feature “due to olivine.” True? We find no olivine feature there. • Simulation of dust emission spectrum Linear superposition of absorbance for (e.g.) 38% water ice, 22% forsterite, 22% orthopyroxene (Mg-rich end member), 8% pyrrohtite, 5% talc or nontronite, 2.5% magnesite, and 2.5% siderite

  16. Summary • Laboratory far-IR absorption spectroscopy of 150 well-characterized minerals • Spectral signatures found in the range of Herschel-PACS for 40 • No features ever found beyond ~140 mm • Funding: NASA-JPL

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