Analysis on the velocity field of non-spherical expansion of Planetary Nebulae

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Planetary Nebulae(PNe) are formed by mass ejection from intermediate mass star at the asymptotic giant branch phase in their evolution. PNe consist of the central high temperature star and the ionized gas. Images obtained with HST reveal much more complicated gaseous flows than previously observed results. Subject of this program is to analyze their velocity fields corresponding to images of HST, and to solve the problem how was the shape of gaseous distribution made under the radiation field of hot central star. Methods for researching this subject s high dispersion spectroscopy in optical regions keeping with spatial information and subsequently to analyze position-velocity diagram. We obtained following results.1. Bipolar like gas flow with large velocity 2V_<exp>=400-600km/sec was found in a halo PN G4-1 in the direction of position angle between 135°and 180°.2. We also found higher velocity gas flows than 2V_<exp>=100km/sec in selected PNe. Its frequency seems to be 50% although sample PNe are limited to a small number.3. We establish observational mode to analyze velocity fields of PNe within accuracy of a few km/sec in the various position angles. Data of position-velocity diagram have been obtained for IC 2149 and NGC 6572.In conclusion, it is considered that various shapes of PNe were made due to the interaction between stellar wind at the stage of asymptotic giant branch and subsequent non-spherical fast mass ejection. For the purpose of applying the method of emission-line profile analysis, we studied about symbiotic star; Z And during recent outburst phase. Our preliminary result suggests that mass losing phenomenon caused by accretion to hot dwarf star should be responsible to make a broad wing component ranging from several hundreds to one thousand km/sec.