小图
这张新的合成图是由NASA/ESA的哈勃空间望远镜上的先进照相机所拍摄，展示了无数恒星“晶体状”的清晰细节。灿烂的疏散星团，NGC265和NGC290，位于距地200000光年处，两者间大致相距65光年。
星团能在引力作用下被紧密的聚合在一起，好比用成百上千颗恒星做成的稠密填充物，叫做球状星团。或者他们能更加疏松的联合在一起，由数千颗恒星所组成的不规则形状，就象这张图中的疏散星团。这个疏散星团中的恒星都相对年轻并且都诞生于同一片星际气体。好比毕业后的老校友不断的迁移，疏散星团里的恒星只有极短的时间是在一起的并且聚后又得在附近恒星合星云的引力拖拽下逐渐远离。大多数疏散星团在数百万年内就回解散，而那些紧密结合的球状星团可以存在数十亿年。
疏散星团能制造出极好极大的真空。恒星们的质量一般都不相同，但在距离上他们都相差不多，在大致相同的一个方向上移动，年龄和化学组成也差不多。他们能被用来研究比较，找出更多关于恒星演化和类似星团的年龄等信息。
小麦哲伦星云，是双星团的所在地，他是量个银河系伴侣星系中最小的一个，由葡萄牙航海家Ferdinand Magellan（1480-1521）所命名。在南半球能用肉眼在TOUCAN看到一块模糊的斑（小麦哲伦星云）。不管是小麦哲伦星云还是大麦哲伦星云都富含气体星云和星团，这些不规则星云在与银河系反复的相互作用下断裂了，形成了强壮的恒星-贯穿整个星云。NGC265和NGC290也许非常适应银河系如此亲近的碰撞。
Two new composite images taken with the Advanced Camera for Surveys onboard the NASA/ESA Hubble Space Telescope show a myriad of stars in crystal clear detail. The brilliant open star clusters, NGC 265 and NGC 290, are located about 200,000 light-years away and are roughly 65 light-years across.
Star clusters can be held together tightly by gravity, as is the case with densely packed crowds of hundreds of thousands of stars, called globular clusters. Or, they can be more loosely bound, irregularly shaped groupings of up to several thousands of stars, like the open clusters shown in this image. The stars in these open clusters are all relatively young and were born from the same cloud of interstellar gas. Just as old school-friends drift apart after graduation, the stars in an open cluster will only remain together for a limited time and gradually disperse into space, pulled away by the gravitational tugs of other passing clusters and clouds of gas. Most open clusters dissolve within a few hundred million years, whereas the more tightly bound globular clusters can exist for many billions of years.
Open star clusters make excellent astronomical laboratories. The stars may have different masses, but all are at about the same distance, move in the same general direction, and have approximately the same age and chemical composition. They can be studied and compared to find out more about stellar evolution, the ages of such clusters, and much more.
The Small Magellanic Cloud, which hosts the two star clusters, is the smaller of the two companion dwarf galaxies of the Milky Way named after the Portuguese seafarer Ferdinand Magellan (1480-1521). It can be seen with the unaided eye as a hazy patch in the constellation Tucana (the Toucan) in the Southern Hemisphere. Both the Small and the Large Magellanic Clouds are rich in gas nebulae and star clusters. It is most likely that these irregular galaxies have been disrupted through repeated interactions with the Milky Way, resulting in the vigorous star-forming activity seen throughout the clouds. NGC 265 and NGC 290 may very well owe their existence to these close encounters with the Milky Way.
自翻，文字和影像资料由拉玛提供
URL：http://www.spacetelescope.org/go ... /html/heic0603.html
大图
[ 本帖最后由 江涛 于 2008-3-11 20:23 编辑 ] |
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联手作品自然要来捧场。江兄为打开了迅速，方便阅读，小图贴上，大图分卷压缩上传好了。
