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OSUG - Terre Univers Environnement OSUG

Séminaire du Jeudi 7 mars 2019

Séminaires doctorants

Thursday March 7th - 11am
IPAG Seminar Room - IPAG

Some things special about NEAs : Geometric and environmental effects on the optical signatures of hydration

by Sandra Potin (IPAG)

Spectral signatures of hydration are detected on a majority of Main-Belt Asteroids (MBAs) corresponding to C-types asteroids, while they seem scarce in the Near-Earth Asteroids (NEAs) population. Two space missions are presently “en route” toward possibly volatile-rich near-Earth asteroids (NEAs) (Hayabusa-2 and Osiris-REX) and the origin of this hydration difference remains to be understood. Signatures of aqueous alteration are also recorded in the optical properties of primitive meteorites, our samples of asteroids.
I will present how the environment of NEAs and the observations themselves can influence the signatures of aqueous alteration. For that purpose, I selected a freshly fallen aqueously altered meteorite, the Mukundpura CM2 chondrite. The effect of observation geometry and the impact of surface texture (comparison of rock and regolith) were investigated using the custom-made reflectance-goniometer SHADOWS, and the impact of thermal processing on the infrared signature was studied in situ using the high-temperature, high-vacuum reflectance cell MIRAGE.

Characterization by HPLC-HRMS of biological molecules in complex organic materials of interest for planetology

by Cédric Wolters (IPAG)

The origin of the complex molecules that lead to life on Earth is discussed around two different hypotheses : an exogenic source with comets and asteroids and an endogenic source with atmospheric hazes. The organic matter present in comets and asteroids formed very early in the history of the Solar System and subsequently evolved chemically by irradiation and by aqueous and thermal alteration. Atmospheric hazes are formed locally by the host star irradiation of the atmosphere. This process is particularly studied for Super-Earth and Mini-Neptune planets, best target hypothesis to find life, in order to constrain some atmospheric composition parameters to reduce the list of possible life-hosting candidates for future observations with new instruments facilities. This topic has strong links with the CDP Origin of Life.
This project couples the analysis of both kinds of astrophysical laboratory simulations in order to establish a list of molecules and identify the diversity and specificity of the samples from the points of view of biochemical molecules. To achieve that goal, new analytical methods have been developed on the mass spectrometer coupled to a liquid chromatography instrument available at IPAG. A new software is also developed to treat this kind of data.
This presentation will treat on a first part the methodology part, from the instrument acquisition perspective to new home-made data treatment software. Then, some preliminary results will be discussed and some insights and scientific results of this work will be presented.

Sous la tutelle de:


Sous la tutelle de:

CNRS Université Grenoble Alpes