Missions

Ensure the exploitation of data from the COSIMA space instrument, a time-of-flight mass spectrometer dedicated to the analysis of the atomic, isotopic and molecular composition of dust particles from comet 67P/Churyumov-Gerasimenko, collected during the Rosetta mission. Among the data not yet used, one goal will be to select the usable spectra in order to deduce the variability of particle composition over the entire data set in positive mode and to constrain the variations in composition between the analyses carried out on surfaces and those carried out beneath the surface.

Activités

Exploitation of composition measurements of around 200 cometary particles. Measurement of ionic and elemental ratios.
Statistical processing of data to highlight possible correlations in composition between the different particles.
Search for elements or fragments not yet detected based on the average total spectrum after optimization of the signal/noise ratio.
Comparison of the spectra measured at the surface of the particles with those measured at the subsurface, after sputtering.
Interpretation of data and recontextualization in a planetological and astrophysical context.

Compétences

• Mass spectrometry (TOF-SIMS)
• Prior experience in handling COSIMA “pipeline” tools
• Statistical processing of a large sample of data: usual statistical tools, PCA, NMF, etc.
• Planetology
• Astrochemistry

Contexte de travail

The agent (M/W) will be assigned to the lISA UMR7583 and the work will take place within the space organic physico-chemistry group, in collaboration with Nicolas Fray and Hervé Cottin, CoIs of the COSIMA experiment; as well as with the entire historic COSIMA team (PI and CoIs) in France and Europe.

Informations complémentaires

LISA (Laboratoire Interuniversitaire des Systèmes Atmosphériques), UMR CNRS 7583 is a mixed research laboratory between Paris-Est Créteil University (UPEC), Université de Paris (UP) and CNRS. It is a component of the Observatory of Sciences of the Universe EFLUVE and of Institut Pierre Simon Laplace (IPSL), a Federation of 6 research laboratories working on environment and climate in the Paris region.
The main research themes in LISA relate to the understanding of the functioning of terrestrial and planetary atmospheres and of the impacts related to the changes of the atmospheric composition due to human activities. The methods used are based on direct observations in the atmosphere, on experimental simulations performed in the laboratory and on various numerical modeling approaches