Line ratios for Helium-like ions: Applications to collision-dominated plasmas

Details Line ratios for Helium-like ions: Applications to collision-dominated plasmas Line ratios for Helium-like ions: Applications to collision-dominated plasmas

2001-07-18

arxiv.org/abs/astro-ph/0107329v1

Astronomy and Astrophysics

Astrophysics

A&A, in press. 10 pages, 2 figures (Tables 4 to 69 and A.1 to A.6 will be only available in electronic form at the CDS via ano

Scientific paper

10.1051/0004-6361:20010959

The line ratios R and G of the three main lines of He-like ions (triplet: resonance, intercombination, forbidden lines) are calculated for CV, NVI, OVII, NeIX, MgXI, and SiXIII. These ratios can be used to derive electron density n_e and temperature T_e of hot late-type stellar coronae and O, B stars from high-resolution spectra obtained with Chandra (LETGS, HETGS) and XMM-Newton (RGS). All excitation and radiative processes between the levels and the effect of upper-level cascades from collisional electronic excitation and from dielectronic and radiative recombination have been considered. When possible the best experimental values for radiative transition probabilities are used. For the higher-Z ions (i.e. NeIX, MgXI, SiXIII) possible contributions from blended dielectronic satellite lines to each line of the triplets were included in the calculations of the line ratios R and G for four specific spectral resolutions: RGS, LETGS, HETGS-MEG, HETGS-HEG. The influence of an external stellar radiation field on the coupling of the 2^3S (upper level of the forbidden line) and 2^3P levels (upper levels of the intercombination lines) is taken into account. This process is mainly important for the lower-Z ions (i.e. CV, NVI, OVII) at moderate radiation temperature (T_rad). These improved calculations were done for plasmas in collisional ionization equilibrium, but will be later extended to photo-ionized plasmas and to transient ionization plasmas. The values for R and G are given in extensive tables, for a large range of parameters, which could be used directly to compare to the observations.

Affiliated with

Also associated with

No associations

Rating

Line ratios for Helium-like ions: Applications to collision-dominated plasmas does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Line ratios for Helium-like ions: Applications to collision-dominated plasmas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Line ratios for Helium-like ions: Applications to collision-dominated plasmas will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-581033