| 翻訳と辞書 |
NGC 7331
NGC 7331 (also known as Caldwell 30) is a spiral galaxy about away in the constellation Pegasus. It was discovered by William Herschel in 1784.〔(The NGC/IC Project ) : ''NGC Discoverers List'' by Bob Erdmann.〕 NGC 7331 is the brightest member of the NGC 7331 Group of galaxies.
The galaxy is similar in size and structure to the galaxy we inhabit, and is often referred to as "the Milky Way's twin",〔 〕 although recent discoveries regarding the structure of the Milky Way may call this similarity into doubt.〔(【引用サイトリンク】title=The Milky Way Has Only Two Spiral Arms )〕
==Retrograde bulge==
In spiral galaxies the central bulge typically co-rotates with the disk but the bulge in the galaxy NGC 7331 is rotating in the opposite direction to the rest of the disk.〔(A Counter-rotating Bulge in the Sb Galaxy NGC 7331 ), F. Prada, C. Gutierrez, R.F. Peletier, C.D. McKeith, THE ASTROPHYSICAL JOURNAL, 463 :L9–L12, 1996 May 20〕 The current bulge may have formed from infalling material, however if it has been there since the formation of the galaxy then it would be difficult to explain how such a situation arose.
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「NGC 7331」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.
|
|