Poster abstract details

We present Herschel/HIFI observations of intermediate-excitation molecular lines in the far-infrared/sub-mm ranges in several young planetary nebulae. The high spectral resolution provided by the heterodyne receiver HIFI allows accurate measurements of the line profiles, whose structure corresponds to the kinematics of the various nebular components, notably fast bipolar outflows and slow shells. We have detected lines of several molecules in our sources, including in particular $^{12}$CO, $^{13}$CO, and H$_{2}$O, as well as other species like NH$_3$, OH, H$_2^{18}$O, HCN, SiO, etc. Wide profiles often showing spectacular line wings have been found. The observed lines are particularly useful to study warm gas, which is not probed by the low-J lines observable from the ground. In particular, we have studied the excitation properties of the high-velocity emission coming from fast bipolar outflows, in which we detect the presence of gas with temperatures over 100-200~K.