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Raman scattered O VI features at 6825 Å and 7082 Å found in symbiotic stars are important spectroscopic tools to probe the mass transfer process. Adopting a Monte Carlo approach, we perform a profile analysis of Raman O VI features of the yellow SySt AG Draconis and make a comparison with the spectrum obtained with CFHT. It is assumed that the accretion flow is convergent on the entering side with enhanced O VI emission and the flux ratio F (1032)/ F (1038)∼1, whereas on the opposite side the flow is divergent with low O VI emission and F (1032/ F (1038)∼2. Our best fit to the spectrum is obtained from our model with a mass-loss rate of the giant ∼4 × 10−7 M⊙ yr−1. A slight red wing excess in the spectrum suggests the presence of bipolar neutral components receding in the directions perpendicular to the binary orbital plane with a speed ∼70km s−1 [ABSTRACT FROM AUTHOR]

We present a high-resolution optical spectrum of the symbiotic nova RR Tel obtained with MIKE at Magellan-Clay telescope. RR Tel is a wide binary system of a hot white dwarf and a Mira with an orbital period of a few decades, where the white dwarf is accreting through gravitational capture of some fraction of material shed by the Mira. We find broad emission features at 6825, 7082, 7023, and 7053 Å, which are formed through Raman scattering of far-UV O VI ⋋⋋ 1032 and 1038 Å, C II ⋋⋋ 1036 and 1037 Å with atomic hydrogen. Raman O VI features exhibit clear double-peak profiles indicative of an accretion flow with a characteristic speed ∼ 30 km s−1, whereas the Raman C II features have a single Gaussian profile. We perform a profile analysis of the Raman O VI by assuming that O VI emission traces the accretion flow around the white dwarf with a fiducial scale of 1 AU. A comparison of the restored fluxes of C II ⋋⋋ 1036 and 1037 from Raman C II features with the observed C II ⋋ 1335 multiplet is consistent with the distance of RR Tel ∼ 2.6 kpc based on interstellar extinction of C II. [ABSTRACT FROM AUTHOR]

We present high-resolution spectra of the symbiotic star V1016 Cygni obtained with the Bohyunsan Optical Echelle Spectrograph in 2003 and 2005, from which we find a broad emission feature at 4881 Å. We propose that this broad feature is formed from Raman scattering of Ne vii λ973 by atomic hydrogen. Thus far, the detection of Raman-scattered lines by atomic hydrogen is limited to O vi λλ1032, 1038 and He ii λλ940, 972 and 1025. With the adoption of a centre wavelength 973.302 Å for Ne vii λ973 and considering an air refractive index nair = 1.000 279 348, the atomic line centre of the Raman-scattered Ne vii feature is determined to be 4880.53 Å. The total cross-section at the line centre of Ne vii λ973 is computed to be 2.62 × 10−22 cm2, with a branching ratio of 0.17. We perform Monte Carlo simulations to fit the Raman-scattered Ne vii λ973. Assuming that the Ne vii and He ii emission regions share the same kinematics with respect to the neutral scattering region, we find that the Raman-scattered He ii λ972 at 4850 Å and Ne vii λ973 at 4881 Å are excellently fitted. We also propose that the He ii and Ne vii emission regions were stationary with respect to the H i region in 2003, but that they were receding from it with a velocity ∼20 km s−1 in 2005. [ABSTRACT FROM AUTHOR]