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The Gould Belt is a partial ring of stars in the Milky Way, about 3000 light years across, tilted toward the galactic plane by about 16 to 20 degrees. It contains many O- and B-type stars, and may represent the local spiral arm to which the Sun belongs—currently the Sun is about 325 light years from the arm's center. The belt is thought to be from 30 to 50 million years old, and of unknown origin. It is named after Benjamin Gould, who identified it in 1879.〔(【引用サイトリンク】 The Gould Belt )〕〔(【引用サイトリンク】 Gould Belt )〕 The belt contains bright stars in many constellations including (in order going more or less eastward) Cepheus, Lacerta, Perseus, Orion, Canis Major, Puppis, Vela, Carina, Crux (the Southern Cross), Centaurus, Lupus, and Scorpius (including the Scorpius-Centaurus Association). The Milky Way also passes through most of these constellations, but a bit southeast of Lupus. Some well-known star-forming regions and OB associations that make up this region include the Orion Nebula and the Orion molecular clouds, the Scorpius-Centaurus OB Association, the Serpens-Aquila Rift and W40, Cepheus OB2, Perseus OB2, and the Taurus-Auriga Molecular Clouds. A theory proposed around 2009 suggests that the Gould Belt formed about 30 million years ago when a blob of dark matter collided with the molecular cloud in our region. There is also evidence for similar Gould belts in other galaxies.〔("Orion's dark secret: Violence shaped the night sky" ), New Scientist, 21 Nov. 2009, pp. 42–5.〕 ==See also== * Gould Belt Survey * Local Bubble * Local Interstellar Cloud * Orion Arm * Perseus Arm 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「Gould Belt」の詳細全文を読む スポンサード リンク
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