Abstract
Optical spectra, images in the main optical emission lines and IR images directed towards the detection of molecular hydrogen, were obtained for 14 planetary nebulae (PNe). Eleven of these comply with the two criteria defining a typePNe (He-rich with a large N/O ratio). All are classified as bipolar, though two of them (A 24 and M 3-5) are either bipolars seen pole-on or elliptical. Shocked molecular hydrogen was detected in eight of these objects, but not in A 14, A 24, and M 1-57. KjPn 6 was tentatively classified as a typePN, though its helium abundance is smaller than the minimum prescribed value and the sum of its nitrogen and oxygen abundances is low. The object is about 800above the galactic plane, is bipolar and shows no trace of molecular hydrogen. The chemical composition of A 24, A 79, M 1-57, and Sh 1-89 indicates that third dredge-up episodes occured in their progenitor star. Shock waves are propagating in the ionized component of A 79, M 1-28 and NGC 2818, and possibly A 14, A 24, and K 3-46. An emission arc in the periphery of Wray 16-22, a typePN, may be interpreted as a bow shock produced by the supersonic motion of this object in the interstellar medium.
