---
title: "Protoplanetary nebula"
id: "protoplanetary-nebula"
project: "Interstellar Travel Safety Procedures Publication2"
url: "https://hedronlabs.clickhelp.co/articles/interstellar-travel-safety-procedures-publication2/protoplanetary-nebula"
updated: 2026-10-01T08:39:33Z
---

# Protoplanetary nebula

##  Protoplanetary nebula
 
A protoplanetary nebula or preplanetary nebula ([Sahai, Sánchez Contreras & Morris 2005](https://en.wikipedia.org/wiki/Protoplanetary_nebula#CITEREFSahaiS%C3%A1nchez_ContrerasMorris2005)) (PPN, plural PPNe) is an [astronomical object](https://en.wikipedia.org/wiki/Astronomical_object) which is at the short-lived episode during a [star](https://en.wikipedia.org/wiki/Star)'s rapid [evolution](https://en.wikipedia.org/wiki/Stellar_evolution) between the late [asymptotic giant branch](https://en.wikipedia.org/wiki/Asymptotic_giant_branch) (LAGB)[^\[a\]^](https://en.wikipedia.org/wiki/Protoplanetary_nebula#endnote_Anone) phase and the subsequent [planetary nebula](https://en.wikipedia.org/wiki/Planetary_nebula) (PN) phase. A PPN emits strongly in [infrared](https://en.wikipedia.org/wiki/Infrared) radiation, and is a kind of [reflection nebula](https://en.wikipedia.org/wiki/Reflection_nebula). It is the second-from-the-last high-luminosity evolution phase in the life cycle of intermediate-mass stars (1–8 [M](https://en.wikipedia.org/wiki/Solar_mass)https://en.wikipedia.org/wiki/Solar_mass). ([Kastner 2005](https://en.wikipedia.org/wiki/Protoplanetary_nebula#CITEREFKastner2005))