A MONTE CARLO STUDY OF FLUX RATIOS OF RAMAN SCATTERED O vi FEATURES AT 6825 AND 7082 Å IN SYMBIOTIC STARS
| Autor: | Jeong-Eun Heo, Young-Min Lee, Ho-Gyu Lee, Byeong-Gon Park, Narae Hwang, Dae-Sub Lee, Hee-Won Lee, Seok-Jun Chang |
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| Rok vydání: | 2016 |
| Předmět: |
Physics
010308 nuclear & particles physics Scattering White dwarf Flux Astronomy and Astrophysics 01 natural sciences Molecular physics symbols.namesake Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science 0103 physical sciences symbols Astrophysics::Solar and Stellar Astrophysics H I region Rayleigh scattering Raman spectroscopy 010303 astronomy & astrophysics Raman scattering Line (formation) |
| Zdroj: | The Astrophysical Journal. 833:75 |
| ISSN: | 1538-4357 |
| DOI: | 10.3847/1538-4357/833/1/75 |
| Popis: | Symbiotic stars are regarded as wide binary systems consisting of a hot white dwarf and a mass losing giant. They exhibit unique spectral features at 6825 \AA\ and 7082 \AA, which are formed via Raman scattering of \ion{O}{6}$\lambda\lambda$ 1032 and 1038 with atomic hydrogen. We adopt a Monte Carlo technique to generate the same number of \ion{O}{6}$\lambda$1032 and $\lambda$1038 line photons and compute the flux ratio $F(6825)/F(7082)$ of these Raman scattered \ion{O}{6} features formed in neutral regions with a simple geometric shape as a function of \ion{H}{1} column density $N_{HI}$. In cylindrical and spherical neutral regions with the \ion{O}{6} source embedded inside, the flux ratio $F(6825)/F(7082)$ shows an overall decrease from 3 to 1 as $N_{HI}$ increases in the range $10^{22-24}{\rm\ cm^{-2}}$. In the cases of a slab geometry and other geometries with the \ion{O}{6} source outside the \ion{H}{1} region, Rayleigh escape operates to lower the flux ratio considerably. For moderate values of $N_{HI}\sim 10^{23}{\rm\ cm^{-2}}$ the flux ratio behaves in a complicated way to exhibit a broad bump with a peak value of 3.5 in the case of a sphere geometry. We find that the ratio of Raman conversion efficiencies of \ion{O}{6}$\lambda\lambda$1032, 1038 ranges from 0.8 to 3.5. Our high resolution spectra of 'D' type HM~Sge and 'S' type AG~Dra obtained with the {\it Canada-France-Hawaii-Telescope} show that the flux ratio $F(6825)/F(7082)$ of AG~Dra is significantly smaller than that of HM~Sge, implying that 'S' type symbiotics are characterized by higher $N_{HI}$ than 'D' type symbiotics. Comment: 15 pages, 9 figures, accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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