Issue |
EAS Publications Series
Volume 58, 2012
ECLA - European Conference on Laboratory Astrophysics
|
|
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Page(s) | 333 - 336 | |
DOI | https://doi.org/10.1051/eas/1258054 | |
Published online | 13 February 2013 |
C. Stehlé, C. Joblin and L. d’Hendecourt (eds)
EAS Publications Series, 58 (2012) 333-336
Photodesorption and product formation in UV-irradiated N2 and NH3 ices under ultra-high-vacuum conditions
Centro de Astrobiología (CSIC-INTA),
Ctra. de Ajalvir, km 4, Torrejón de Ardoz, 28850
Madrid,
Spain
The accretion and desorption processes of gas molecules on cold grains play an important role in the evolution of dense clouds and circumstellar regions around YSOs. Given the low temperatures in dark cloud interiors (10–20 K), thermal desorption is negligible and most molecules are expected to stick to grains leading to depletion in the gas phase. Laboratory simulations of these processes under astrophysically relevant conditions are required for their understanding. The use of ultra-high-vacuum conditions minimalizes contamination by background water accretion. This introduces a radical improvement, allowing the study of photodesorption and the detection of products at very low abundances in a water-free ice matrix. We studied UV-photoprocessing of pure NH3 and N2 ices under ultra-high-vacuum conditions using the Interstellar Astrochemistry Chamber. The photodesorbed molecules, and the volatile products released upon photolysis and warm-up, were detected in situ by quadrupole mass spectroscopy.
© The Author(s) 2013