* Astronomy

Title: Raman Scattered Ne VIIlambda973 at 4881 angstroms in the Symbiotic Star V1016 Cygni
Author: Hee-Won Lee, Jeong-Eun Heo, Byeong-Cheol Lee

We present the 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 angstroms. We propose that this broad feature is formed from Raman scattering of Ne VIIlambda973 by atomic hydrogen. Thus far, the detection of Raman scattered lines by atomic hydrogen is limited to O VIlambdalambda1032, 1038 and He IIlambdalambda940, 972 and 1025. With the adoption of the center wavelength 973.302 angstroms of Ne VIIlambda973 and consideration of the air refractive index of nair=1.000279348, the atomic line center of the Raman scattered Ne VII feature is determined to be 4880.53 angstroms. The total cross section at the line center of Ne VIIlambda973 is computed to be 2.62 x 10^-22 cm^2 with the branching ratio of 0.17. We perform Monte Carlo simulations to fit the Raman scattered Ne VIIlambda973. 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 IIlambda972 at 4850 angstroms and Ne VIIlambda973 at 4881 angstroms 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.

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