An Etymological Dictionary of Astronomy and Astrophysics

A short-lived transition object between the → asymptotic giant branch (AGB) and → planetary nebula phases. See also
→ post-asymptotic giant branch star (post-AGB).

See also: → pre-; → planetary; → nebula. The more commonly used term, → protoplanetary nebula, is a misnomer and must be avoided. Indeed → protoplanetary is widely used to refer to disks around → pre-main sequence stars. Since the term → protoplanet is used to denote planets undergoing formation, the use of the term “protoplanetary nebula” to mean a completely different kind of object is an unfortunate choice (Sahai et al. 2005, ApJ 620, 948).