J/A+A/674/A171 Opacity tables for NaHe (Allard+, 2023)
Temperature and density dependence of line profiles of sodium perturbed
by helium.
Allard N.F., Myneni K., Blakely J.N., Guillon G.
<Astron. Astrophys. 674, A171 (2023)>
=2023A&A...674A.171A 2023A&A...674A.171A (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics
Keywords: opacity - line: profiles - brown dwarfs - white dwarfs
Abstract:
Ultracool stellar atmospheres and hot exoplanets show absorption by
alkali resonance lines severely broadened by collisions with neutral
perturbers. In the coolest and densest atmospheres, such as those of T
dwarfs, NaI and KI broadened by molecular hydrogen and helium can come
to dominate the entire optical spectrum. The effects of Na-He
collision broadening are also central to understanding the opacity of
cool DZ white dwarf stars.
In order to be able to construct synthetic spectra of brown dwarfs and
cool DZ white dwarfs, where helium density can reach several
1021cm-3, Na-He line profiles of the resonance lines have been
computed over a wide range of densities and temperatures.
Unified line profiles that are valid from the core to the far wings at
high densities are calculated in the semiclassical approach using
up-to-date molecular data including electronic spin-orbit coupling
from the sodium atom. Far wings are extended to more than 4000cm-1
from the line center when the helium density can reach 1021cm-3 at
5000K.
We present a comprehensive study of Na-He collisional profiles at
high density, and temperatures from 5000K, which is the temperature
prevailing in the atmosphere of ultra-cool DZ white dwarf stars, down
to 1K, which is the temperature in liquid helium clusters. Collision
broadening and shift parameters within the impact approximation
obtained in the semiclassical and quantum theory using our new
accurate molecular data are presented.
Description:
The files contain the opacity tables for NaHe, the programs to read
the tables, examples for the D1 and D2 components of the resonance
line, a file README.pdf for the description of the opacity tables and
explanations of their use.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
README.pdf 512 132 Description of the opacity tables and
explanations of their use
prog/* . 3 Programa to read the tables
D1/* . 17 Examples for the D1 components of the
resonance line
D2/* . 17 Examples for the D2 components of the
resonance line
--------------------------------------------------------------------------------
Acknowledgements:
Nicole Allard, nicole.allard(at)obspm.fr
(End) Patricia Vannier [CDS] 20-Apr-2023