Protoplanetary nebula

A protoplanetary nebula or preplanetary nebula (PPN) is an astronomical object which is at the short-lived episode during a star's rapid stellar evolution between the late asymptotic giant branch (LAGB)[a] phase and the subsequent planetary nebula (PN) phase. A PPN emits strongly in infrared radiation, and is a kind of reflection nebula. It is the second-from-the-last high-luminosity evolution phase in the life cycle of intermediate-mass stars.

The name protoplanetary nebula is an unfortunate choice due to the possibility of confusion with the same term being sometimes employed when discussing the unrelated concept of protoplanetary disks.