本帖最后由 gohomeman1 于 2009-8-12 23:08 编辑
今天的APOD是不规则星系NGC 55,但是今天的APOD非常慢的说。
http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/ap090812.html
以下的翻译来自北京天文台。
2009 August 12
Irregular Galaxy NGC 55
Credit & Copyright: Don Goldman
Explanation:
Irregular galaxy NGC 55 is thought to be similar to the Large Magellanic Cloud (LMC). But while the LMC is about 180,000 light-years away and is a well known satellite of our own Milky Way Galaxy, NGC 55 is more like 6 million light-years distant and is a member of the Sculptor Galaxy Group. Classified as an irregular galaxy, in deep exposures the LMC itself resembles a barred disk galaxy. However, spanning about 50,000 light-years, NGC 55 is seen nearly edge-on, presenting a flattened, narrow profile in contrast with our face-on view of the LMC. Just as large star forming regions create emission nebulae in the LMC, NGC 55 is also seen to be producing new stars. This higly detailed galaxy portrait highlights a bright core crossed with dust clouds, telltale pinkish star forming regions, and young blue star clusters in NGC 55.
说明:
不规则星系NGC55被认为结构与大麦哲伦星系(LMC)类似。但是大麦哲伦星系距离我们大约18万光年远,是我们银河系的一个卫星星系,而NGC55距离们约600万光年远,是玉夫星系团的一员。大麦哲伦星系也被归类为不规则星系,在深空影像中类似一个棒状圆盘星系。而NGC55大约覆盖了5万光年,从侧面看去,扁平狭窄的外观与大麦哲伦星系正面外观形成鲜明的对比。就像大麦哲伦星系内的巨大恒星形成区域形成了发射星云一样,可以看到NGC55内也正在新诞生恒星。这张高清晰星系影像突出了尘埃星云中的明亮星核,显而易见的粉色恒星形成区域,以及年轻的蓝色恒星团。 |
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