翻訳と辞書 Words near each other ・ Prototheora geniculata ・ Prototheora malawiensis ・ Prototheora merga ・ Prototheora monoglossa ・ Prototheora parachlora ・ Prototheora petrosema ・ Protophyta benigna ・ Protophyta castanea ・ Protopidius ・ Protopine ・ Protopine 6-monooxygenase ・ Protopithecus ・ Protoplane Ultra ・ Protoplanet ・ Protoplanetary disk ・ Protoplanetary nebula ・ Protoplasm ・ Protoplasman ・ Protoplast ・ Protopolybia chartergoides ・ Protopolybia exigua ・ Protopone ・ Protopop Jovan ・ Protopope ・ Protopopinci ・ Protopopintsi ・ Protopopov ・ Protoporphyrin ・ Protoporphyrin IX ・ Protoporphyrinogen IX Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Protoplanetary nebula ： ウィキペディア英語版 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) 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 (1–8 ). ==Naming== 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. The name protoplanetary nebula is a consequence of the older term planetary nebula, which was chosen due to early astronomers looking through telescopes and finding a similarity in appearance of planetary nebula to the gas giants such as Neptune and Uranus. To avoid any possible confusion, suggests employing a new term preplanetary nebula which does not overlap with any other disciplines of astronomy. They are often referred to as post-AGB stars, although that category also includes stars that will never ionize their ejected matter. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Protoplanetary nebula」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.