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| Paper: |
Non Coherent Continuum Scattering as a Polarization Mechanism
of the Enigmatic Ba II D1 Line |
| Volume: |
489, Solar Polarization 7 |
| Page: |
107 |
| Authors: |
del Pino Alemán, T.; Trujillo Bueno, J.; Uitenbroek, H. |
| Abstract: |
Line scattering polarization can be strongly affected by Rayleigh scattering by neutral hydrogen and Thomson scattering by free electrons. The assumption that continuum polarization can be modeled as coherent scattering, an excellent approximation far from the spectral line, yields a continuum depolarization when applied to an intrinsically unpolarizable spectral line. However, the radiation field is not always constant over the spectral line and continuum scattering has to be treated non-coherently. A recent investigation showed that the redistribution of the spectral line radiation due to the non coherence of the continuum scattering can significantly modify the shape of the emergent fractional linear polarization profiles, even yielding emission Q/I features in intrinsically unpolarizable lines. Here we show an application to the enigmatic D1 line of Ba II at 4934 Å, neglecting the hyperfine structure of the 18% of the barium isotopes whose nuclear spin is non-zero. We show that with this assumption Q/I signals above the continuum polarization level can be produced in solar atmospheric models representative of polar faculae. |
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