Séminaire IPAG

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Origin and evolution of cosmic PAHs and their characterization in dust analogues and meteorites

jeudi 9 juin 2022 - 11h00

Hassan Sabbah - IPAG
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Large carbonaceous molecules such as polycyclic aromatic hydrocarbons (PAHs) and fullerenes are abundant species in astrophysical environments. Targeting specific species of these families raises the question of their formation in particular in the hot and dense envelopes of evolved stars. This has motivated a number of research groups to produce cosmic dust analogues using various techniques. Laboratory analysis of extraterrestrial matter such as meteorites can also provide additional clues regarding the origin of these molecules and their physical and chemical evolution. In this talk, I will present a new experimental setup called AROMA (Astrochemistry Research of Organics with Molecular Analyzer). The experimental set-up consists of a microprobe laser desorption ionization source and a segmented linear quadrupole ion trap connected to an orthogonal time of flight mass spectrometer. We have analyzed several samples of meteorites including Murchison and Allende, the two most studied carbonaceous chondrites, as well as Almahata Sitta. The same technique is used to analyze cosmic dust analogues such as those produced by the Stardust machine. Hundreds of peaks are identified in the mass spectra with notable discrepancies across the different type of samples. We present here our ability to use these discrepancies for a better understanding of the chemical history of each sample. Ultimately, our approach can contribute in elucidating the role of these species in the formation and evolution of carbonaceous cosmic grains.

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Hôtes : Véronique Vuitton

Salle Manuel Forestini, 414 rue de la piscine, 38400 Saint Martin d'Hères