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Grains In Ionized Nebulae: Spectral Line Diagnostics, J. B. Kingdon, Gary J. Ferland, W. A. Feibelman

Physics and Astronomy Faculty Publications

The depletion of condensable elements onto grains in gaseous nebulae can provide evidence that dust is well mixed with the ionized gas. Al and CA are two of the most depleted elements in the general interstellar medium, and it is therefore important to measure their abundances within the ionized region of nebulae. We compute a large grid of photoionization models and identify sets of line ratios which are relatively insensitive to stellar and nebular parameters, and are thus excellent diagnostics for determining relative abundances. Based on the absence of the [Ca II] λλ7291, 7324 doublet and the detection of …