Blue wing of the 2p-1s He_2_ line

DOI

The shape and broadening of He lines affects radiative transport in dense, He-rich, stellar atmospheres. At wavelengths inaccessible for direct observation, we rely on theoretical calculations of self-broadening to support stellar structure and spectral modeling. In this work, we examine lines of He due to 1s-2p and 2p-3s transitions. The line profiles are analyzed in terms of a unified theory of spectral line broadening using ab initio potential energies that have been recently determined. For temperatures up to 20000K, the linear dependence of width and shift on gas density and the non-linear dependence on temperature of the Lorentzian core of the resonance line are described. Beyond the conventional symmetrical Lorentzian core, we show that they are asymmetrical and have significant additional contributions on the short wavelength side. This blue asymmetry is a consequence of maxima in the corresponding He2 potential energy difference curves at short and intermediate internuclear distance. Over a limited range of density and temperature, laboratory measurements in the visible and near infrared can be used to validate the potentials that underlie the spectral line profile theory, which is useful for modeling spectra over the extreme ranges of temperature and density encountered in stellar and planetary atmospheres.

Identifier
DOI http://doi.org/10.26093/cds/vizier.35590070
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/A+A/559/A70
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/559/A70
Related Identifier https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/559/A70
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/A+A/559/A70
Provenance
Creator Allard N.F.; Deguilhem B.; Monari A.; Gadea F.X.; Kielkopf J.F.
Publisher CDS
Publication Year 2013
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics