Two-Photon Absorption by Hydrogen Molecules: Origin of the 2175 Angstrom Astronomical Band?

The near UV spectra of OB stars in our galaxy are often dominated by a very broad extinction band peaking at ~2175 Angstroms. Forty years after its discovery, the origin of this band remains unknown, although interstellar dust particles are generally assumed to be the carriers. Here we report that t...

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Bibliographic Details
Main Authors Sorokin, Peter P, Glownia, James H
Format Journal Article
LanguageEnglish
Published 03.08.2006
Subjects
Physics - Astrophysics of Galaxies
Physics - Cosmology and Nongalactic Astrophysics
Physics - Earth and Planetary Astrophysics
Physics - High Energy Astrophysical Phenomena
Physics - Instrumentation and Methods for Astrophysics
Physics - Solar and Stellar Astrophysics
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Summary:The near UV spectra of OB stars in our galaxy are often dominated by a very broad extinction band peaking at ~2175 Angstroms. Forty years after its discovery, the origin of this band remains unknown, although interstellar dust particles are generally assumed to be the carriers. Here we report that two-photon absorption by hydrogen molecules in gaseous clouds enveloping OB stars can lead to a band peaking at ~2175 Angstroms. We present astronomical spectral evidence supporting our proposal that this nonlinear absorption mechanism accounts for the lambda2175 feature.
Bibliography:LANL LA-UR-06-1898
DOI:10.48550/arxiv.astro-ph/0608092