Nebula Dust

Planetary nebulae are nebulae that form from the gaseous shells that are ejected from low-mass asymptotic giant branch stars when they transform into white dwarfs. These nebulae are emission nebulae with spectral emission that is similar to the emission nebulae found in star formation regions. Technically, they are an HII region because most hydrogen will be ionized. However, planetary nebulae are denser and more compact than the emission nebulae in star formation regions. Planetary nebulae are so called because the first astronomers who observed these objects thought the nebulae resembled the disks of planets, although they are not related to planets. Our sun is believed to become one of these 12 billion years after the suns formation.
Protoplanetary nebula
A protoplanetary 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) phase and the following planetary nebula (PN) phase. During the AGB phase, the star undergoes mass loss, emitting a circumstellar shell of hydrogen gas. When this phase comes to an end, the star enters the PPN phase.