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The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It constitutes the visible portions of the Cygnus Loop (radio source W78, or Sharpless 103), a large but relatively faint supernova remnant. The source supernova exploded some 5,000 to 8,000 years ago, and the remnants have since expanded to cover an area roughly 3 degrees in diameter (about 6 times the diameter, or 36 times the area, of the full moon). The distance to the nebula is not precisely known, but Far Ultraviolet Spectroscopic Explorer (FUSE) data supports a distance of about 1,470 light-years. The Hubble Space Telescope captured several images of the nebula. The analysis of the emissions from the nebula indicate the presence of oxygen, sulfur, and hydrogen. This is also one of the largest, brightest features in the x-ray sky. September 24, 2015 new images and videos of the Veil Nebula were released, with an explanation of the images. == Components == In modern usage, the names ''Veil Nebula'', Cirrus Nebula, and Filamentary Nebula generally refer to all the visible structure of the remnant, or even to the entire loop itself. The structure is so large that several NGC numbers were assigned to various arcs of the nebula. There are three main visual components: * The Western Veil (also known as Caldwell 34), consisting of NGC 6960 (the "Witch's Broom", "Finger of God",〔Tom Trusock, ("Small Wonders: Cygnus ..." ), () "The Veil", ''Cloudy Nights Telescope Reviews''〕 or "Filamentary Nebula"〔) near the foreground star 52 Cygni; * The Eastern Veil (also known as Caldwell 33), whose brightest area is NGC 6992, trailing off farther south into NGC 6995 and IC 1340; and * Pickering's Triangle (or Pickering's Triangular Wisp), brightest at the north central edge of the loop, but visible in photographs continuing toward the central area of the loop. NGC 6974 and NGC 6979 are luminous knots in a fainter patch of nebulosity on the northern rim between NGC 6992 and Pickering's Triangle.〔(【引用サイトリンク】 work=Results for NGC 6974 )〕〔(【引用サイトリンク】 work=Results for NGC 6979 )〕 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「Veil Nebula」の詳細全文を読む スポンサード リンク
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