HIGH-VELOCITY FLOW IN THE CENTRAL PART OF THE HIGHLY EVOLVED PLANETARY NEBULA ABELL 30

We obtained a high dispersion [OIII] lambda-5007 spectrum of the highly evolved planetary nebula, Abell 30 (PK 208 + 33 degrees 1 = IRAS 08440 +1803). We found a high velocity component in the profile whose expansion velocity derived from its full width at half maximum, 166 km s-1, and from the full width at zero intensity, VFWZI 450 km s-1, in addition to the two velocity components from the previously identified knots. Moreover, from the position of the broad component, we determine the systemic velocity as Vsys = 13 km s-1 in the frame of the Local Standard of Rest. These narrow components are attributed to J2 and J3-H4 identified by Jacoby (1979) and Hazard et al. (1980). Because Abell 30 is famous as a hydrogen deficient planetary nebula, we suggest that its cetnral star, having already shed its hydrogen envelope to expose the helium core, is now shedding its helium envelope. Abell 30, is therefore, considered to have experienced a secondary ejection phase. Moreover, the evidence of existence of the fast stellar wind suggests that there is a dramatic effect on the material around the central star. We briefly discuss the origin of such a high velocity flow.