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| Paper: |
Raman Scattered He II 4332 and Photoionization Model in the Symbiotic Star V1016 Cygni |
| Volume: |
482, 10th Pacific Rim Conference on Stellar Astrophysics |
| Page: |
195 |
| Authors: |
Lee, H.-W.; Heo, J.-E.; Lee, B.-C. |
| Abstract: |
Symbiotic stars are wide binary systems of a white dwarf and a mass losing giant. They exhibit unique Raman scattered features as a result of inelastic scattering of far UV line photons by atomic hydrogen. Co-existence of a far UV He II emission region and a thick H I region in symbiotic stars is necessary for the formation of Raman-scattered features blueward of hydrogen Balmer emission lines. Being a single electron atom, He II has the same atomic structure as the hydrogen atom and hence emits far UV emission lines that are slightly blueward of hydrogen Lyman lines. These far UV He II emission lines can be Raman scattered to appear blueward of hydrogen Balmer lines. In particular, the symbiotic star V1016 Cyg is found to exhibit Raman scattered He II 4332 feature in the BOES high resolution spectrum. Our profile fitting of Raman scattered He II 4332 is consistent with the mass loss geometry proposed by Jung & Lee (2004). We use the photoionization code ‘CLOUDY' to estimate the far UV He II emission lines and make comparisons with the observed Raman scattered He II 4332 blueward of Hγ in the high resolution echelle V1016 Cyg. The emission nebula is assumed to be of uniform density of 108 cm–3 that is illuminated by a black body characterized by its temperature and total luminosity. With our comparisons we conclude that the Raman scattered He II features are consistent with the existence of a photoionized nebula by a hot black body source with temperature 7–8× 104 K with a luminosity 1038erg s–1. |
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