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| Paper: |
Sun-as-a-star line formation |
| Volume: |
9, Cool Stars, Stellar Systems, and the Sun: Sixth Cambridge Workshop |
| Page: |
91 |
| Authors: |
Rutten, Robert J. |
| Abstract: |
Spectral line formation in the upper solar photosphere and temperature-minimum region is discussed to examine the effectiveness of spatially averaged '1D' modeling in solar and stellar applications. Problems associated with NLTE radiative transfer are described for the two-level atom, one bound level with a continuum, three bound levels, and for multiple levels. Successful applications of 1D modeling are reviewed where solar photospheric optical lines are used to calibrate stellar abundance determinations. The homogeneity or 1D LTE-RE formation of the sun is doubted, and the atmosphere is described as being highly dynamic. The LTE-RE assumption can be applied to the spatially averaged upper photosphere, but the problems associated with the NLTE effects must be considered to investigate the fine elements of solar structure. |
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