2025年7月14日
NGC 2685: The Helix Galaxy
Image Credit & Copyright: Stefan Thrun
Explanation: What is going on with this galaxy? NGC 2685 is a confirmed polar ring galaxy – a rare type of galaxy with stars, gas and dust orbiting in rings perpendicular to the plane of a flat galactic disk. The bizarre configuration could be caused by the chance capture of material from another galaxy by a disk galaxy, with the captured debris strung out in a rotating ring. Still, observed properties of NGC 2685 suggest that the rotating helix structure is remarkably old and stable. In this sharp view of the peculiar system also known as Arp 336 or the Helix galaxy, the strange, perpendicular rings are easy to trace as they pass in front of the galactic disk, along with other disturbed outer structures. NGC 2685 is about 50,000 light-years across and 40 million light-years away in the constellation of the Great Bear (Ursa Major).
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极环星系NGC 2685
影像提供与版权: Stefan Thrun
说明: NGC 2685已被证实是个极环星系。在这种罕见形态的星系里，由恒星、气体和尘埃所组成的绕极环状构造，垂直于扁平的星系盘面。这种奇特的组态，可能源自扁碟状星系捕获了另一个星系的物质所致，而被拉扯过来的碎片碰巧形成绕极的环形结构。不论如何，由观测所得出的NGC 2685特性显示，这个旋转的环状结构极为古老且稳定。这幅清晰影像所呈现的奇特星系NGC 2685，也有Arp 336或螺旋星系（Helix galaxy）之称号。它怪异的垂直绕极环及其他受扰的外部结构，因为通过星系盘的前方而清楚可辨。NGC 2685位于大熊座方向，离我们有4千万光年远，大小则在50,000光年左右。
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