LERMA UMR8112

Laboratoire d’Études du Rayonnement et de la Matière en Astrophysique et Atmosphères



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LERMA UMR8112

Observatoire de Paris LERMA - UMR8112
77 avenue Denfert Rochereau - 75014 Paris

5 place Jules Janssen - 92190 MEUDON

4 place Jussieu Tour 32-33 - 3eme ET - 75005 Paris

Université de Cergy-Pontoise

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This website uses a graphic template that is designed and produced as part of the project for the harmonization of CNRS websites.

Project manager

Marco Cucchi (Pôle-web, DirCom, CNRS)

Web template development (Web team, Communications Department, CNRS)

  • Pascal Verrier: web development
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Development of the plugin "Seminar"

Amaury Adon

Development of the initial versions of the template

Frank de Albuquerque - Jean-Baptiste Pressac (CNRS) - Valérie Pierre (CNRS) - Benoît Chassigneux - Julien Barnier (GRS) - Jean-Christophe Monferran (LAHIC) - Stéphane Pouyllau (CRHST)

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© CNRS Photothèque

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Séminaires à venir

Vendredi 5 mars 2021, 14h00
Visioconférence via Zoom,
Laboratory astrophysics studies of VUV and X-ray induced photodesorption from interstellar ice analogues
Mathieu BERTIN
LERMA-Jussieu-PSL
résumé :
The recent advances in space and ground based telescopes (ALMA, NOEMA…) have allowed the detection of more and more molecules in the gas phase in the coldest regions of the interstellar medium - ISM (star-forming regions, protoplanetary disks…). The puzzling detection of these gaseous species, including small organic molecules, in media where the temperature is very low (~ 10-100 K), is currently a major and still open question, directly linked to the astrochemical richness. Most of the observed molecules are indeed expected to either directly form or accrete on the surface of dust grains, and cannot thermally desorb in the regions where they are detected. Their observation requires thus non-thermal desorption processes, among which the desorption induced by UV or X-ray photons – so-called photodesorption – is a promising candidate. However, its role still needs to be clarified, especially in the case of the desorption of small organics molecules for which both the quantitative yields and the underlying mechanisms are lacking.

I will present the outcomes of recent laboratory astrophysics studies base on the use of the monochromatic and tunable synchrotron radiation, dedicated to understand and quantify the photodesorption processes in both the vacuum UV (7-13,6 eV) and soft X-rays (500 – 1500 eV) energy ranges. The role played by the photon energy and of the molecular ice composition on the desorption yields will be highlighted, and a special focus will be made on the case of photodesorption of complex organics molecules.

 
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