APOD090915： 新月星云NGC 6888

http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/ap090915.html

NGC 6888: The Crescent Nebula

                               
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Credit & Copyright: [email=dlp%20at%20iac%20dot%20es]Daniel López[/email],IAC
Explanation:
NGC 6888, also known as the Crescent Nebula, is acosmic bubble about 25 light-years across, blown bywinds from its central, bright, massive star.Thisbeautiful portrait of the nebula is from theIsaac Newton Telescope atRoque de los MuchachosObservatory in the Canary Islands.It combines a composite color imagewith narrow band data that isolates light from hydrogenand oxygen atoms in the wind-blown nebula.The oxygen atoms produce the blue-green hue that seems to enshroudthe detailed folds and filaments.NGC 6888's central star is classified as a[url=http://cfa-www.harvard.edu/%7Epberlind/atlas/htmls/wrstars.html]Wolf-Rayet star[/url](WR 136).The star is shedding its outer envelope in a strongstellarwind,ejecting the equivalent of the Sun's mass every 10,000 years. The nebula's complex structures are likely the result of thisstrong wind interacting with material ejected in an earlier phase.Burning fuel at a prodigious rate andnear theendof its stellar life this star should ultimately go out with a bang in aspectacular supernova explosion.Found in the nebula richconstellation Cygnus,NGC 6888is about 5,000 light-years away.

北馆尚未翻译，此翻译来自成大，过几天只怕又要被屏蔽了吧。
http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/ap090915.html

NGC 6888: 弦月星雲
影像提供與版權: Daniel López, IAC
說明:
NGC 6888又名為弦月星雲(Crescent Nebula)，中心有一大質量的明亮恆星和它恆星風所吹出的25光年大泡泡。這張美麗影像拍攝於加那利群島的Roque de los Muchachos天文台下的亞薩克牛頓望遠鏡(Isaac Newton Telescope, INT)，透過氫、氧原子輻射的窄波段影像疊加而成，其中氧原子輻射影像以藍綠色套色，以呈現雲氣的細節與層次。NGC 6888中心的恆星是一顆沃夫-瑞葉型恆星(Wolf-Rayet star;WR 136)，它強烈的恆星風，將恆星外層的氣殼吹走，大約每一萬年所拋出的質量和一個太陽相當。此星雲的複雜結構，可能是強烈的恆星風和恆星早期噴發的物質交互作用的結果。這種大質量恆星會以極高的速度燃燒燃料，現正處於恆星演化的末期，終將超新星爆炸結束它的生命之旅。NGC 6888位於星雲群集的天鵝座(Cygnus)內，距離我們大約有5000光年。

今天的APOD大图，2258X1500，图很慢。
http://apod.nasa.gov/apod/image/0909/NGC6888_Lopez.jpg

                               
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中心区域存在一个洞？此处应该是中心星所在，而不是旁边的那颗亮星吧。

图片真的非常清晰！