J/A+A/559/A70 Blue wing of the 2p-1s He2 line (Allard+, 2013)
Blue satellites on He lines due to He-He collisions.
Allard N.F., Deguilhem B., Monari A., Gadea F.X., Kielkopf J.F.
<Astron. Astrophys. 559, A70 (2013)>
=2013A&A...559A..70A 2013A&A...559A..70A
ADC_Keywords: Line Profiles ; Atomic physics
Keywords: lines: profiles - stars: atmospheres - brown dwarfs - white dwarfs
Abstract:
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.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 29 2100 Blue wing of the 2p-1s He2 line, using ab initio
potentials, with nHe=1019cm-3 (Fig. 6 of paper)
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See also:
J/A+A/543/A159 : Line profiles of neutral Na perturbed by H2 (Allard+, 2012)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 4 I4 K T Temperature (1000, 3000 and 6000)
9- 15 F7.3 0.1nm lambda [568/583] Wavelength λ
19- 29 E11.7 --- Int Intensity I(λ)
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Acknowledgements:
Nicole Allard, nicole.allard(at)obspm.fr
(End) Patricia Vannier [CDS] 18-Sep-2013