J/A+A/713/A16 NIR K 4p-5s doublet asymmetrical shape (Allard+, 2026)
Asymmetrical shape of the near-infrared K 4p-5s doublet perturbed by He and H2.
Allard N.F., Kielkopf J.F.
<Astron. Astrophys. 713, A16 (2026)>
=2026A&A...713A..16A 2026A&A...713A..16A (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Models ; Line Profiles
Keywords: line: profiles - stars: atmospheres - brown dwarfs
Abstract:
The goal of this paper is to provide an exhaustive study of the
K 4p-5s doublet at 1.243/1.252um perturbed by He and H2 under the
physical conditions of brown dwarfs. This work is applicable to
analysis of the ESO SupJup Survey J-band spectra, such as those of
Luhman 16. Line profiles of this doublet computed within a unified
line-shape theory exhibit a blue asymmetrical behavior. This effect
increases with He and H2 density, and as a result, the full treatment
of the infrared K doublet reveals strong effects on its opacity
outside the impact approximation. For He and H2 perturber densities
larger than 1019cm-3 (0.4bar), the impact approximation breaks
down and is not applicable for calculating the shape of the line
profiles and their line core parameters.
Description:
The opacity tables are valid to He and H2 perturber density =
1019cm-3. The accurate computation of line profiles from
collision broadening at higher density requires use of a Fourier
transform of the autocorrelation function. It has to be done in
collaboration with N. Allard.
Each table (tableD1KHe4p5sT12501e19.omg,
tableD1KH24p5sT12501e19.omg, tableD2KHe4p5sT12501e19.omg and
tableD2KH24p5sT12501e19.omg) contains coefficients for the
expansion of the line profile opacity in density at a gas temperature
T=1250K. They have been done for the D1 and D2 lines for an He/H2
density = 1019 cm-3. They use the density expansion described in
Section 3.3 of Allard et al. (2019A&A...628A.120A 2019A&A...628A.120A). The tables are
consistently formatted and may be read by the Fortran or Python
programs that are supplied with them.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
readme_4p5s.pdf 512 129 Description of the tables and
explanations of their use
example_KH2.tar 1054 42572 Examples
tablesKHeKH2_4p5s.tar 1069 1846 Tables
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See also:
J/A+A/543/A159 : Line profiles of neutral Na perturbed by H2 (Allard+, 2012)
J/A+A/559/A70 : Blue wing of the 2p-1s He2 line (Allard+, 2013)
J/A+A/589/A21 : K-H2 line shapes for cool brown dwarfs spectra (Allard+, 2016)
J/A+A/619/A152 : Variation of MgHe line profile with temperature (Allard+ 2018)
J/A+A/628/A120 : Stellar atmosphere opacity Na broadened by H2 (Allard+, 2019)
J/A+A/657/A121 : Collisional effects in blue wing of Balmer-alpha
(Allard+, 2022)
J/A+A/674/A171 : Opacity tables for NaHe (Allard+, 2023)
J/A+A/683/A188 : Stellar atmosphere opacity K broadened by He (Allard+, 2024)
J/A+A/703/A71 : Stellar atmosphere opacity K broadened by H2 (Allard+, 2025)
Acknowledgements:
Nicole Allard, nicole.allard(at)obspm.fr
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 11-Aug-2026