Back to the Abstract

	1 Introduction
	2 Source sample
	3 New CO observations
	4 Calculation of physical parameters from the CO data
	5 Mass, momentum and energy carried by PPN outflows
	6 Characteristic duration of the strong mass acceleration
	7 Gas acceleration due to radiation pressure in late AGB stars and PPNe
	8 Mass and dynamics of PPNe: Statistical results
	9 Other mechanisms for the acceleration of the nebular material
	10 Conclusions
	References