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Open Astronomy

formerly Baltic Astronomy

Editor-in-Chief: Barbuy, Beatriz


IMPACT FACTOR 2018: 0.350

CiteScore 2018: 0.24

SCImago Journal Rank (SJR) 2018: 0.202
Source Normalized Impact per Paper (SNIP) 2018: 0.144

ICV 2017: 121.03

Open Access
Online
ISSN
2543-6376
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Volume 23, Issue 3-4

Issues

Diffusional Separation of Calcium Isotopes in Chemically Peculiar Stellar Atmospheres

L. Sapar / A. Sapar / R. Poolamäe / A. Aret
Published Online: 2017-02-18 | DOI: https://doi.org/10.1515/astro-2017-0180

Abstract

Diffusional separation of calcium isotopes in the atmospheres of hot chemically peculiar stars is studied. In addition to the usual radiative acceleration effect, the light-induced drift is taken into account. We propose that microturbulence in stable stellar atmospheres is generated by the interaction between plasma particles and radiative flux. Formulae for the microturbulent velocity and microturbulence diffusion coefficient are derived. Data on isotopic and hyperfine splitting of the calcium spectral lines have been collected as an input file. The equilibrium Ca isotope concentrations are found in model computations, iteratively correcting the radiative acceleration values. The general picture of Ca isotope stratification is found to be similar to our previous results obtained for Hg isotopes: dominating overabundance of the heaviest isotope. Diffusional stratification of Ca isotope concentrations in atmospheres of late B and early A spectral types are computed and visualized in figures. The isotope abundances on the inner boundary surface were fixed to be the solar ones. The computed Ca II infrared triplet line profiles are compared with the observed line profiles in a high-dispersion spectrum of HD 175640.

Keywords: stars: atmospheres; stars: chemically peculiar; stars: abundances; diffusion; turbulence

REFERENCES

About the article

Received: 2014-11-10

Accepted: 2014-12-12

Published Online: 2017-02-18

Published in Print: 2014-12-01


Citation Information: Open Astronomy, Volume 23, Issue 3-4, Pages 171–187, ISSN (Online) 2543-6376, DOI: https://doi.org/10.1515/astro-2017-0180.

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© 2014 L. Sapar et al., published by De Gruyter Open. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. BY-NC-ND 3.0

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