The Formation of the Double Gaussian Line Profiles of the Symbiotic Star AG Peg
We analyze high dispersion emission lines of the symbiotic nova AG Peg, observed in 1998, 2001, and 2002. The H$\alpha$ and H$\beta$ lines show three components, two narrow and one underlying broad line components, but most other lines, such as HI, HeI, and HeII lines, show two blue- and red-shifted components only. A recent study by Lee & Hyung (2018) suggested that the double Gaussian lines emitted from a bipolar conic shell is likely to form Raman scattering lines observed in 1998. In this study, we show that the bipolar cone with an opening angle of 74$^{o}$, which expands at a velocity of 70 kms$^{-1}$ along the polar axis of the white dwarf, can accommodate the observed double line profiles in 1998, 2001, and 2002. We conclude that the emission zone of the bipolar conic shell, which formed along the bipolar axis of the white dwarf due to the collimation by the accretion disk, is responsible for the double Gaussian profiles.