New Atomic Data for the Astrophysically Important Ion, Fe~X

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Session 112 -- Models and Synthetic Spectroscopy
Display presentation, Saturday, January 15, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[112.01] New Atomic Data for the Astrophysically Important Ion, Fe~X

G.A.Doschek (NRL), A.K.Bhatia (GSFC)

New atomic data for Fe~X have been calculated using the distorted wave approximation. These data should be useful for analysis of EUVE and HST high resolution stellar spectra. The calculations include the 54 levels of the 3s$^2$3p$^5$, 3s3p$^6$, 3s$^2$3p$^4$3d, and 3s3p$^5$3d configurations. Electron impact collision strengths were calculated at five incident electron energies: 9.0, 18.0, 27.0, 36.0 and 45.0 Ry. Spontaneous radiative decay probabilities have also been computed. Relative spectral line intensities were calculated for all astrophysically important transitions, for an ion temperature of $10^6$ K and electron densities ranging from $10^8$ to $10^{12}$ cm$^{-3}$. The line intensities were obtained by computing excitation rate coefficients assuming a Maxwellian electron velocity distribution, and solving the equations of detailed balance for the level populations. In addition, the effects of proton excitation and radiative excitation from a photosphere have been considered. The relative line intensities have been compared to available solar observations in the UV and EUV wavelength regions. Four previously unidentified EUV lines in solar spectra are classed as Fe~X transitions as a result of this comparison. While there is general agreement between calculated and experimental line intensities, there are also some interesting discrepancies. This work is supported by a NASA grant from the Ultraviolet and Visible Astrophysics Branch of the Astrophysics Division under Contract No. W17,362.

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