Determinations of temperature and density for solar-like Stars using Si XI soft X-ray emission lines

Abstract

We study temperature and density sensitivities of ratios of Si XI soft X-ray emission lines, in the wavelength range of 43--54Å. The typical temperature of the formation of the analyzed lines is around 1.6~MK, which makes this analysis complementary to the analysis of He-like triplets being sensitive to hotter plasma. We present theoretical calculations and compare them with ratios obtained from high-resolution X-ray spectra of five solar-like stars: Procyon, $\alpha$ Cen A$&$B, $\epsilon$ Eri, and Capella. We find that our results are in good agreement with results obtained by other authors through different diagnostics, namely the analysis of density- and temperature-sensitive He-like triplet lines. We further estimate the coronal pressure and filling factors from Si~XI lines in this study.

arXiv comment21 pages, 6 figures, Accepted in AJ

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• Electron density diagnostic for hot plasmas in coronal regime by using B-like ions
• Soft X-ray emissions of highly charged Si VII--Si XII in cool star--Procyon