No CrossRef data available.
Published online by Cambridge University Press: 30 August 2012
Our sample of round/elliptical double-shell PNe around central stars (CSs) with H-rich surface chemistry covers all evolutionary phases across the HRD. By means of high-resolution and high-S/N spectra we determine bulk matter velocities of the inner wind-driven rims and the maximum (= post-shock) gas velocities of the surrounding thermally expanding shells. Studying the details of the internal kinematics allows a look at processes of PN formation and at PN expansion history helping, for instance, to determine expansion distances.