The discovery of the extremely luminous supernova SN 2006gy, possibly
interpreted as a pair instability supernova, renewed the interest in very
massive stars. We explore the evolution of these objects, which end their life
as pair instability supernovae or as core collapse supernovae with relatively
massive iron cores, up to about 3M⊙.Comment: 16 pages, 5 figures, ApJ accepte