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Implementing TOPbase/Iron Project: Continuous Absorption from Fe II

Charles R. Cowley·Manuel Bautista
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Abstract

We discuss implementation of TOPbase and Iron Project opacities for stellar spectral codes. We use a technique employed by Peach, where a Boltzmann-averaged cross section is calculated for selected temperatures, and the opacity obtained from double interpolation in temperature and wavelength. It is straightforward to include {\it all} levels for which cross sections have been calculated. Boltzmann-averaged cross sections for Fe II show a local maximum between 1700 and 2000[A]. We suggest this feature arises from 3d^5 4snl to 3d^5 4pnl transitions within Fe II. IUE spectra of iron-rich CP stars show local minima in this region. Theoretical calculations of a representative stellar continuum demonstrate that Fe II photoionization contributes significantly to the observed minima.

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Charles R. Cowley, Manuel Bautista. 2003-01-03. Implementing TOPbase/Iron Project: Continuous Absorption from Fe II. https://doi.org/10.1046/j.1365-8711.2003.06488.x

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