2009A&A...499..943L


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.13CET12:06:49

2009A&A...499..943L - Astronomy and Astrophysics, volume 499, 943-954 (2009/6-1)

R-matrix electron-impact excitation data for B-like Si and its application in cool stars.

LIANG G.Y., WHITEFORD A.D. and BADNELL N.R.

Abstract (from CDS):

We present the results of an intermediate coupling frame-transformation R-matrix calculation for the electron-impact excitation of Si9+. The target and close-coupling expansions are both taken to be the 125 fine-structure levels (58 LS terms) belonging to the configurations 2sx2py (x+y=3) and 2sα2pβ3l (α+β=2, l=s, p, and d). Due to the additional resonances included in our calculation, we find significant differences at low temperatures with the widely used n=2-2 excitation rates, also obtained with the R-matrix method, as well as with the n=2-3 excitation rates calculated by using the distorted wave (DW) approximation. We present a list of prominent transition lines and comparisons with SERTS and Hinode/EIS EUV spectra of the solar corona, SUMER observations for the quiet sun, as well as Chandra LETG and Rocket soft X-ray spectra of the Procyon corona and solar flares, respectively. Line emissivities of some transitions are enhanced up to 40% when compared with those obtained from using the previous atomic data at the same electron density (1.6x109cm–3) and temperature (1.3x106K). The comparison with Chandra LETG observation of Procyon reveals that the 3s-2p line flux was significantly underestimated (by a factor of 4-5) in previous analyses. Some EUV and soft X-ray emission line ratios are ne-sensitive and Te-insensitive. Estimated electron densities from them shift downwards due to the new resonant-enhanced excitation data used in the present modelling.

Abstract Copyright:

Journal keyword(s): atomic data - atomic processes - plasmas - stars: coronae - X-rays: stars - ultraviolet: solar system

Simbad objects: 2

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Number of rows : 2

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 * alf Aur SB* 05 16 41.35871 +45 59 52.7693 1.33 0.88 0.08 -0.52 -0.96 G3III: 1133 0
2 * alf CMi SB* 07 39 18.11950 +05 13 29.9552 0.82 0.79 0.37 -0.05 -0.28 F5IV-V+DQZ 1742 0

    Equat.    Gal    SGal    Ecl

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2019.11.13-12:06:49

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