SPRING project : InfraRouGe SPectroscopy of hydrated planetary materials

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**Summary

Infrared spectroscopy of hydrated planetary materials
We are trying to characterize the hydration of the surface of Mars and meteorites and build a link with comets and dark asteroids.

Measure and understand the hydrated mineralogy of Mars, chondrites and asteroids
In this project we are trying to understand the mineralogy of the surface of Mars. In the IR-screw, two absorptions are present in a global way : an absorption in the visible, responsible for the red color and an absorption at 3-µm. In this work we try to understand the latter, probably related to the presence of one or more hydrated minerals. We are also trying to understand the presence of carbonates observed very recently. To do this we test a mechanism, which is the formation by a gas-solid reaction, between a mineral surface and CO2-gas.
Meteorites are unique samples because they provide information on the early stages of the solar system’s formation. These rocks are a natural sampling of asteroids and possibly comets. Within the various meteorite families, carbonaceous chondrites are considered to be the most primitive. These show the action of liquid water at some point in their history, as they contain a significant amount of hydrated minerals. They therefore probably reflect the very first presence of liquid water in the Solar System.

Experimental characterization of natural samples (meteorites) and analogues
To understand the presence of carbonates on the surface of Mars, we have developed a system to measure carbonation kinetics by gas-solid reaction. To understand the hydrated mineralogy of carbonaceous chondrites we have attacked three approaches : i) infrared powder spectroscopy ii) thermogravimetric analyses (TGA) iii) XANES spectroscopy at the iron threshold (synchrotron source). In order to build a link with hydrated asteroids, we carry out measurements with the spectro-photogoniometer available at the IPAG. We also carry out photometric measurements in collaboration with the University of Bern.