Abstract
High-resolution spectrophotometric data of the central zone of the Br-type planetary nebula M2-52 are presented. The nebula has a rich spectrum, with high and low excitation lines. The chemical composition derived from the spectra shows that He and N are very enhanced in M2-52. Thus, this object can be classified as an extreme Peimbert's Type I PN. The chemical composition of the ionized gas is: He/H = 0.165+/-0.010, O/H = (2.6+/-0.5)×10-4, N/O = 2.3+/-0.3, Ne/O = 0.37+/-0.10, Ar/O = (9.2+/-2.0)×10-3 and S/O > 2.0×10-3. The expansion velocity of the nebula is, on average, about 20+/-2 km s-1, but the low ionization species (N+ and S+) seem to systematically show slightly lower expansion velocities (18 km s-1) than O+ + and He+ which have v[exp] = 20 km s-1, while H+ and He++ have v[exp] ~ 22 km s-1. This behavior could indicate that the outer zones of the ionized gas are being decelerated by the molecular ring located around the central star.
