Institut des Sciences Moléculaires d'Orsay




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Home > Research Teams > Molecular systems, Astrophysics and Environment > Research > Theme 3: Grains and solids in astrophysics > Carbonaceous interstellar dust characterization and lifecycle

Carbonaceous interstellar dust characterization and lifecycle

The interstellar medium (ISM) is populated with different forms of carbonaceous solids: polyaromatic hydrocarbons, (hydrogenated-)amorphous carbons and (nano-)diamonds.

The polyaromatic materials give rise to characteristic emission bands known as the Aromatic Infrared Bands (AIBs), observed in the ISM in the mid- infrared. Still unidentified with a definite carrier, they are actively studied with our laboratory experiments dedicated to analogues production (Nanograins set-up), aiming at forming relevant size distributions and perform spectroscopic characterizations.
Amorphous solids made of C and H, the hydrogenated amorphous carbons (HAC or a-C:H), constitute another important interstellar dust component that we study experimentally (Sical and Insolite experiments). They were early detected in absorption against background Galactic center infrared sources. Since then, a large number of observations confirmed their ubiquitous presence in the diffuse ISM.

The composition of these interstellar solids and the links among them are driven by environmental parameters (elemental abundance, density, reactant nature, radiations, temperature, time scales) and results from the extreme interstellar medium physico-chemical conditions. We explore and simulate their interactions with cosmic rays on large accelerators (GANIL in Caen, GSI in Darmstadt, TANDEM in Orsay) and with VUV photons (laser and continuum sources) to define their fundamental spectroscopic properties, their fate under astrophysical conditions and provide data sets for astrophysical models.