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28 March 2024 |
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Article overview
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Non-local thermodynamic equilibrium stellar spectroscopy with 1D and 3D models - I. Methods and application to magnesium abundances in standard stars | Maria Bergemann
; Remo Collet
; Anish M. Amarsi
; Mikhail Kovalev
; Gregory Ruchti
; Zazralt Magic
; | Date: |
21 Dec 2016 | Abstract: | We determine Mg abundances in 8 standard stars using 1D hydrostatic and
averaged 3D model atmospheres. The stars cover a large range of Teff from 4286
to 6500 K, log g from 1.64 to 4.44, and metallicity from -3.0 to solar.
Radiative transfer calculations are performed in local thermodynamic
equilibrium (LTE) and in non-LTE (NLTE). The linelist includes Mg I lines
across the full stellar spectrum, from the optical to the infrared H-band. We
find that: a) Mg abundances determined from the infrared spectra are as
accurate as the optical diagnostics, b) Mg I line profiles are best fit by the
NLTE models, but the NLTE abundance effects on most Mg I lines are minor, c)
mean 3D NLTE approach can be used with confidence for dwarfs and subgiants, d)
the solar Mg abundance is 7.67 +- 0.02 dex, which is higher than the previous
mean 3D NLTE photospheric estimate by Scott et al. (2015), e) the NLTE
calculations with mean 3D models lead to ~ 0.15 dex higher Mg abundances in all
program stars compared to 1D LTE, with some variation depending on stellar
metallicity. However, normalising the results to the mean 3D NLTE solar
measurement, we obtain [Mg/Fe] estimates that are barely different from 1D LTE
or 1D NLTE. | Source: | arXiv, 1612.7355 | Services: | Forum | Review | PDF | Favorites |
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