Protoplanetary nebula
TYPE OF ASTRONOMICAL OBJECT
Protoplanetary nebulae; Preplanetary nebula; Post-AGB Star; Proto-planetary nebulae
A protoplanetary nebula or preplanetary nebula (PPN, plural PPNe) is an astronomical object which is at the short-lived episode during a star's rapid evolution between the late asymptotic giant branch (LAGB) phase and the subsequent planetary nebula (PN) phase. A PPN emits strongly in infrared radiation, and is a kind of reflection nebula.