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Non-local Thermodyn...
Non-local Thermodynamic Equilibrium Stellar Spectroscopy with 1D and 〈3〉 Models. I. Methods and Application to Magnesium Abundances in Standard Stars
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- Bergemann, Maria (författare)
- Max Planck Institute for Astronomy
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- Collet, Remo (författare)
- Aarhus University,Australian National University
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- Amarsi, Anish M. (författare)
- Australian National University,Max Planck Institute for Astronomy
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- Kovalev, Mikhail (författare)
- Max Planck Institute for Astronomy
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- Ruchti, Greg (författare)
- Lund University,Lunds universitet,Astronomi - Har omorganiserats,Institutionen för astronomi och teoretisk fysik - Har omorganiserats,Naturvetenskapliga fakulteten,Lund Observatory - Has been reorganised,Department of Astronomy and Theoretical Physics - Has been reorganised,Faculty of Science
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- Magic, Zazralt (författare)
- Natural History Museum of Denmark,University of Copenhagen
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(creator_code:org_t)
- 2017-09-15
- 2017
- Engelska.
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 847:1
- Relaterad länk:
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http://dx.doi.org/10...
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https://arxiv.org/pd...
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https://lup.lub.lu.s...
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https://doi.org/10.3...
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Abstract
Ämnesord
Stäng
- We determine Mg abundances in six Gaia benchmark stars using theoretical one-dimensional (1D) hydrostatic model atmospheres, as well as temporally and spatially averaged three-dimensional (〈3D〉) model atmospheres. The stars cover a range of Teff from 4700 to 6500 K, log g from 1.6 to 4.4 dex, and [Fe H] from -3.0 dex to solar. Spectrum synthesis calculations are performed in local thermodynamic equilibrium (LTE) and in non-LTE (NLTE) using the oscillator strengths recently published by Pehlivan Rhodin et al. We find that: (a) Mg abundances determined from the infrared spectra are as accurate as the optical diagnostics, (b) the NLTE effects on Mg I line strengths and abundances in this sample of stars are minor (although for a few Mg I lines the NLTE effects on abundance exceed 0.6 dex in 〈3D〉 and 0.1 dex in 1D, (c) the solar Mg abundance is 7.56 ± 0.05 dex (total error), in excellent agreement with the Mg abundance measured in CI chondritic meteorites, (d) the 1D NLTE and 〈3D〉 NLTE approaches can be used with confidence to analyze optical Mg I lines in spectra of dwarfs and sub-giants, but for red giants the Mg I 5711 line should be preferred, (e) low-excitation Mg I lines are sensitive to the atmospheric structure; for these lines, LTE calculations with 〈3D〉 models lead to significant systematic abundance errors. The methods developed in this work will be used to study Mg abundances of a large sample of stars in the next paper in the series.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- galaxies: abundances
- line: formation
- radiative transfer
- stars: abundances
- stars: late-type
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