planetary nebula
1Planetary nebula — Planetary Plan et*a*ry, a. [Cf. L. planetarius an astrologer, F. plan[ e]taire planetary. See {Planet}.] 1. Of or pertaining to the planets; as, planetary inhabitants; planetary motions; planetary year. [1913 Webster] 2. Consisting of planets; as …
2planetary nebula — n. [from its resemblance, when viewed through a telescope, to a PLANET] a glowing, expanding nebula that forms around a collapsing star …
3Planetary nebula — A planetary nebula is an emission nebula consisting of a glowing shell of gas and plasma formed by certain types of stars when they die. The name originated in the 18th century because of their similarity in appearance to giant planets when… …
4Planetary Nebula M2-9 — For other uses of Butterfly Nebula , see Butterfly Nebula (disambiguation). Minkowski 2 9 (M2 9) Observation data (Epoch J2000) …
5planetary nebula — Astron. an expanding shell of thin ionized gas that is ejected from and surrounds a hot, dying star of about the same mass as the sun; the gas absorbs ultraviolet radiation from the central star and reemits it as visible light by the process of… …
6Planetary nebula luminosity function — (PNLF) is a secondary distance indicator used in astronomy. It makes use of the [O III| [O III] λ5007 forbidden line found in all planetary nebula which are members of the old stellar populations (Population… …
7planetary nebula — noun a nebula that was once thought to be a star with its planets but is now thought to be a very hot star surrounded by an expanding envelope of ionized gases that emit a fluorescent glow because of intense radiation from the star • Hypernyms:… …
8planetary nebula — noun Date: 1785 a usually compact luminous ring shaped nebula that is composed of matter which has been ejected from a hot star at its center …
9planetary nebula — noun Astronomy a ring shaped nebula formed by an expanding shell of gas round an ageing star …
10planetary nebula — noun A nebulosity surrounding a dying star, consisting of material expelled by the star. Syn: PN …
