雷神的头盔(NGC 2359)和行星状星云
http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/image/0903/Thor4Andreo800.jpg说明: 这幅影像右方的雷神头盔(NGC 2359; Thor's Helmet)，像是在美丽的星野裡眺望著远方。这片位在大犬座内的宽广星场，宽度约有1.5度，相当於三个满月的跨幅。如你仔细检视影像的左下角，或许可以找到它凝视的目标是个黯淡浑圆的星云。雷神的头盔宽度约有30光年，所以对北欧神祇来说也是庞大无比。这座头盔实际上是个星际泡泡，位在泡泡中心附近的明亮大质量恆星，所发出高速之恆星风扫过周遭的分子云而形成了这个天体。这颗中心星是一颗沃夫-瑞叶恆星，是种处在前超新星演化阶段的超热巨星。对比之下，这个黯淡浑圆的天体是个行星状星云，是滨临死亡低质量恆星所拋出的外层气壳。雷神头盔离我们约有15,000光年远。
转自成大 讲解很到位，图也很好看，这是用哈勃拍的吗？ 影像很漂亮！ 这个估计是地面望远镜拍的。Hubble图片应该能清晰得多。
APOD原文部分：
Credit & Copyright: Rogelio Bernal Andreo, Ray Gralak，也看不出什么信息啊。
链接大图，2812 × 1976px，1.6MB
http://apod.nasa.gov/apod/image/0903/Thor4Andreo.jpg 视野蛮大的 ::070821_04.jpg:: http://antwrp.gsfc.nasa.gov/apod/image/0701/thor_cfht_big.jpg 8# gohomeman1
不知道这图是从什么波段拍摄，真耀眼 应该是地面拍摄的吧，昨晚在APOD以前历史中翻出来的。现在一时不记得是哪一年了。 Astronomy Picture of the Day
2007 January 30
http://antwrp.gsfc.nasa.gov/apod/image/0701/thor_cfht.jpg
Thor's Helmet from CFHT
Credit & Copyright: Jean-Charles Cuillandre (CFHT) & Giovanni Anselmi (Coelum Astronomia), Hawaiian Starlight
Explanation: NGC 2359 is a striking emission nebula with an impressive popular name - Thor's Helmet Sure, its suggestive winged appearance might lead some to refer to it as the "duck nebula", but if you were a nebula which name would you choose? By any name NGC 2359 is a bubble-like nebula some 30 light-years across, blown by energetic winds from an extremely hot star seen near the center and classified as a Wolf-Rayet star. Wolf-Rayet stars are rare massive blue giants which develop stellar winds with speeds of millions of kilometers per hour. Interactions with a nearby large molecular cloud are thought to have contributed to this nebula's more complex shape and curved bow-shock structures. NGC 2359 is about 15,000 light-years distant toward the constellation Canis Major. 内容基本相同，就不翻译了。
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