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NGC 7424 is a barred spiral galaxy located 37.5 million light-years away in the southern constellation Grus (the Crane). Its structure and diameter (about 100,000 light-years) make it similar to our own galaxy, the Milky Way.〔 〕 It is called a "grand design" galaxy because of its well defined spiral arms. One supernova and two ultraluminous X-ray sources have been discovered in NGC 7424. ==Characteristics== NGC 7424 is intermediate between normal spirals (SA) and strongly barred galaxies (SB). Other features include the presence of a central ring-like structure and a relatively low core brightness relative to the arms. The redder color of the prominent bar indicates an older population of stars while the bright blue color of the loose arms indicates the presence of ionised hydrogen and clusters of massive young stars. NGC 7424 is listed as a member of the IC 1459 Grus Group of galaxies, but is suspected of being a "field galaxy"; that is, not gravitationally bound to any group.〔 〕 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 7424」の詳細全文を読む スポンサード リンク
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