Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Line Shielding

  • Steven B. Charnley
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_893-3


Line shielding refers to the situation in which molecules whose photo-destruction is controlled by absorption of radiation in spectral lines can have their destruction rates greatly reduced in interstellar clouds. This arises when there is sufficient material between the source of UV radiation and the cloud interior such that molecules in the exterior layers of the cloud preferentially absorb the dissociating photons, thus leading to molecules in the cloud interior experiencing a greatly attenuated photon flux. Line shielding is important for the survival of H2 and CO in molecular clouds near energetic astrophysical sources.

See Also


Bioorganic Chemistry Spectral Line Photon Flux Isotopic Fractionation Interstellar Medium 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.NASA Goddard Space Flight Center, Code 699Solar System Exploration Division, Code 691, Astrochemistry LaboratoryGreenbeltUSA