Soft X-ray emission lines of Fe VII-Fe XVI in stellar coronae in the range 49-106 angstrom

G. Y. Liang, G. Zhao

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Abstract

Observational data for the cool star Procyon (Obs_IDs 63, 1461 and 1224) available from the Chandra Data Public Archive were co-added and analysed. Using the R-matrix excitation data generated under the auspices of previous Iron/Opacity and the ongoing Atomic Data for Astrophysical Plasma projects for n = 3 complexes, and up to n = 4 complexes for some ions, we derived line emissivities of highly charged iron ions (Fe VII-Fe XVI) over temperatures of abundant ionic stages in equilibrium. By combining the line emissivities with the emission measure presented by Raassen et al., theoretical line fluxes and line intensity ratios were predicted, and the theoretical spectra was constructed by assuming a Gaussian profile with instrumental broadening (0.06 angstrom). By making a detailed comparison between the observational results and predictions, some emission lines from iron ions in stellar coronae (including solar and Procyon) were identified for the first time, and some mis-assignments in the literature were found.

Original languageEnglish
Pages (from-to)1987-2000
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume405
Issue number3
DOIs
Publication statusPublished - 1 Jul 2010

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Keywords

  • line identification
  • analytical methods
  • coronae stars
  • X-rays
  • electron-impact excitation
  • benchmarking atomic data
  • effective collision strengths
  • fine-structure transitions
  • iron project
  • extreme-unltraviolet
  • solar-flare
  • chandra
  • astrophysics
  • spectrum

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