J/A+A/665/A33 Non-LTE abundances for Na, Mg and Al (Lind+, 2022)
Non-LTE abundance corrections for late-type stars from 2000Å to 3µm:
I. Na, Mg, and Al.
Lind K., Nordlander T., Wehrhahn A., Montelius M., Osorio Y., Barklem P.S.,
Afsar M., Sneden C., Kobayashi C.
<Astron. Astrophys. 665, A33 (2022)>
=2022A&A...665A..33L 2022A&A...665A..33L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Abundances ; Spectroscopy ; Optical
Keywords: radiative transfer - stars: abundances - stars: atmospheres -
stars: late-type - techniques: spectroscopic
Abstract:
It is well known that cool star atmospheres depart from local thermo-
dynamic equilibrium (LTE). Accurate abundance determination requires
taking those effects into account, but the necessary non-LTE
calculations are often lacking. Our goal is to provide detailed
estimates of NLTE effects for FGK type stars for all spectral lines
from the ultraviolet to the infrared that are potentially useful as
abundance diagnostics. The first paper in this series focusses on the
light elements Na, Mg and Al. The code PySME is used to compute
curves-of-growth for 2158 MARCS model atmospheres in a wide parameter
range. Nine abundance points are used to construct individual line
curves-of-growth by calculating the equivalent widths of 35 Na lines,
134 Mg lines, and 34 Al lines. The lines are selected from the
ultra-violet to the near infrared wavelength range. We demonstrate the
power of the new grids with LTE and NLTE abundance analysis by means
of equivalent width measurements of five benchmark stars; the Sun,
Arcturus, HD84937, HD140283 and HD122563. For Na, the NLTE abundances
are lower than in LTE and show markedly reduced line-to-line scatter
in the metal- poor stars. For Mg, we confirm previous reports of a
significant 0.25 dex LTE ionization imbalance in metal-poor stars that
is only slightly improved in NLTE (0.18dex). LTE abundances based on
MgII lines agree better with models of Galactic chemical evolution.
For Al, NLTE calculations strongly reduce a 0.6dex ionization
imbalance seen in LTE for the metal-poor stars. The abundance
corrections presented in this work are in good agreement with previous
studies for the subset of lines that overlap, except for strongly
saturated lines.
Description:
The three tables contain LTE and non-LTE equivalent widths for Na, Mg
and Al that can be used to compute LTE and NLTE abundances by
interpolation to observationally inferred stellar parameters and
equivalent widths.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
na.dat 48 781991 Equivalent widths for Na lines (table B1)
mg.dat 48 3489416 Equivalent widths for Mg lines (table B2)
al.dat 48 1041874 Equivalent widths for Al lines (table B3)
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Byte-by-byte Description of file: na.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Elem Element name
4- 8 A5 --- Line Line identifier
12- 15 I4 K Teff Effective temperature
18- 20 F3.1 [cm/s2] logg Surface gravity
22- 26 F5.2 [-] [Fe/H] Metallicity
29- 31 F3.1 km/s Vturb Microturbulence velocity
33- 36 F4.1 [-] [Na/Fe] [-1.0/1.0]? The [Na/Fe] abundance
38- 42 F5.3 [0.1pm] logWL log10 of LTE equivalent width in mÅ
44- 48 F5.3 [0.1pm] logWN log10 of NLTE equivalent width in mÅ
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Byte-by-byte Description of file: mg.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Elem Element name
4- 8 A5 --- Line Line identifier
12- 15 I4 K Teff Effective temperature
18- 20 F3.1 [cm/s2] logg Surface gravity
22- 26 F5.2 [-] [Fe/H] Metallicity
29- 31 F3.1 km/s Vturb Microturbulence velocity
33- 36 F4.1 [-] [Mg/Fe] [-1.0/1.0]? The [Mg/Fe] abundance
38- 42 F5.3 [0.1pm] logWL log10 of LTE equivalent width in mÅ
44- 48 F5.3 [0.1pm] logWN log10 of NLTE equivalent width in mÅ
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Byte-by-byte Description of file: al.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Elem Element name
4- 8 A5 --- Line Line identifier
12- 15 I4 K Teff Effective temperature
18- 20 F3.1 [cm/2] logg Surface gravity
22- 26 F5.2 [-] [Fe/H] Metallicity
29- 31 F3.1 km/s Vturb Microturbulence velocity
33- 36 F4.1 [-] [Al/Fe] [-1.0/1.0]? The [Al/Fe] abundance
38- 42 F5.3 [0.1pm] logWL log10 of LTE equivalent width in mÅ
44- 48 F5.3 [0.1pm] logWN log10 of NLTE equivalent width in mÅ
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Acknowledgements:
Karin Lind, karin.lind(at)astro.su.se
(End) Patricia Vannier [CDS] 09-Aug-2022