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 \pm 0.010 , O/H = ( 2.6 \pm 0.5 ) \times 10 ^ { -4 } , N/O = 2.3 \pm 0.3 , Ne/O = 0.37 \pm 0.10 , Ar/O = ( 9.2 \pm 2.0 ) \times 10 ^ { -3 } and S/O > 2.0 \times 10 ^ { -3 } .
The expansion velocity of the nebula is , on average , about 20 \pm 2 km s ^ { -1 } , but the low ionization species ( N ^ { + } and S ^ { + } ) seem to show systematically slightly lower expansion velocities ( 18 km s ^ { -1 } ) than O ^ { + + } and He ^ { + } which have v _ { exp } = 20 km s ^ { -1 } while H ^ { + } and He ^ { + + } present v _ { exp } \sim 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 .