Infrared Spectroscopy of Minerals from Primitive Meteorites: An IR Snapshot of

an Early Solar System.

A. Morlok1,4, M. Koehler2,4, O.N. Menzies3,4, M. M. Grady1,4

1 The Natural History Museum, London2 Institut fuer Planetologie, Muenster

3 Imperial College, London 4 IARC

© European Southern Observatory

Astronomical Infrared Spectra

Formation of a Solar System

© Bill Hartmann

Primitive Meteorites: Components

Calcium-Aluminum Rich Inclusions Chondrules and Matrix

Mainly Silicates, e.g.:Olivine (Mg,Fe)2SiO4

Pyroxene (Mg,Fe)SiO3

‘Glass’

Highly refractory phases, e.g.:Corundum Al2O3

Hibonite CaAl12O19

Melilite Ca2MgSi2O7

Ca2Al2SiO7

What ?

?

(Mid-)infrared spectra from sub-micron dust clouds, young solar systems, circumstellar discs etc. obtained with earth and space based telescopes

Mid-infrared analysis of sub-micron powder of mineral separates and components, from primitive meteorites for comparison with these astronomical spectra

Aim: Comparison of laboratory infrared data of minerals and components with astronomical spectra

© European Southern Observatory

Challenges-Sample Preparation:

-’Pure’ grains/material needed But primitive meteorites are very fine grained, most mineral grains <<100m

-Characterization: What are we actually measuring ?-Preparation of tiny grains for identification, measurement of chemical composition, estimation of homogeneity

-Infrared Measurements-Small amounts of material (~ng) Difficult to prepare/handle Danger of artefacts

-Generally: Efficiency of process – each individual grain counts !

Sample Preparation

Cleaning with Isopropanol and Deionised Water

Picking

Embedding

PolishingCharacterisation

Separation

Grinding FT-IR Analysis (at last)

Separation

Sample

How: FT-IR Techniques (Microscope)-Perkin Elmer AutoImage FT-IR microscope system for mid-infrared: 4000cm-1 to 650cm-1 (2.5m to ~16m), spectral resolution 4cm-1

Transmission/Absorbance

Source

Sample

Detector

+High Quality+Common

-Thin Samples Needed

Reflectance

Source

Sample

Detector

+Easy&Fast

-(Less Common)

ATR

Source

Sample

Detector

+High Quality

-Artefacts-Resolution

Results: Enstatites from Primitive Meteorites I

TW Hya

-Pictoris

Enstatite (En99) From Primitive Meteorite

8.0

8.5

9.0

9.5

10.0

10.5

11.0

11.5

12.0

60 65 70 75 80 85 90 95 100

Enstatite Mol%

Ban

d P

ositi

on in

Mic

ron

Results: Enstatites from Primitive Meteorites

Compact, Melilite/Spinel-rich Inclusion (Vigarano CV3.3)

Wark-Lovering Rim:Diopside, Forsterite, Spinel

Interior:Melilite, Spinel

Material Separated ‘In Situ’ from Polished Thick Section

A

8 9 10 12 13m11

TW Hya

-Pictoris

Conclusions & Outlook

-Analyses over a wider range of wavelengths needed (far IR !)-Systematic analysis of all types of components like CAI and chondrules-Effects of environment (temperature…) and size

andso…

-Mid-infrared spectra of components and minerals from primitivechondrites can be easily measured with a variety of techniques-Preliminary comparison with astronomical spectra shows potential -But much more work has to be done ….