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| Paper: |
One Peculiarity Common to the Sun's and Symbiotic Stars' Spectra |
| Volume: |
154, Cool Stars, Stellar Systems and the Sun: Tenth Cambridge Workshop |
| Page: |
1101 |
| Authors: |
Klochek, N. V.; Nikonova, M. V. |
| Abstract: |
For almost half of the rare symbiotic stars, there is a wide and strong emission line at 6825 AA. This line has recently been identified to be due to the Raman scattering of the O VI resonance line lambda 1032 AA by neutral hydrogen (Schmid 1989, A&A, 211, L31): lambda^-1_Raman = lambda^-1_(O VI) - lambda^-1_(Ly alpha). This line is considered to be observable only in the spectra of symbiotic stars under atmospheric conditions appropriate for its excitation. However, in spite of this, and taking into consideration the existence of the strong emission lines of O VI lambda1032 AA and neutral hydrogen lambda1216 AA in the UV range of the Sun's spectrum, an attempt was made to reveal the Raman scattering in the visual spectrum of the Sun, namely, in the neighborhood of lambda 6825 AA. High-accuracy spectral measurements of the Sun-as-a-star and of center of the solar disk were used for this purpose. Well-defined variations of the continuum level with profiles typical for emission lines were revealed in this spectral range on the background of the narrow photospheric lines. The width of this emission band in the Sun-as-a-star spectrum is about 12 AA with an intensity of about 1%. For the spectrum of the centre of the Sun's disk these values are about 6 AA and 0.5%, respectively. If these peculiarities are actually due to Raman scattering, then the use of the line lambda 6825 AA in observations might become a new research tool in studying the transition region and the corona of the Sun. |
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