NGC 660: 极环星系

NGC 660: 极环星系

NGC 660: Polar Ring Galaxy
Image Credit & Copyright: Mike Selby

Explanation: What kind of strange galaxy is this? This rare structure is known as a polar ring galaxy, and it seems to have two different rings of stars. In this galaxy, NGC 660, one ring of bright stars, gas, and dark dust appears nearly vertical, while another similar but shorter ring runs diagonally from the upper left. How polar ring galaxies obtain their striking appearance remains a topic of research, but a leading theory holds that it is usually the result of two galaxies with different central ring planes colliding. NGC 660 spans about 50,000 light years and is located about 40 million light years away toward the constellation of the Fish (Pisces). The featured image was captured recently from Observatorio El Sauce in Chile.

Tomorrow’s picture: open space

NGC 660: 极环星系
影像提供与版权: Mike Selby

说明: 这是那种奇特的星系？具有这种罕见结构的天体称为极环星系，而它则看似拥有2个不同的恒星环。例如在星系NGC 660里，除了有个由明亮恒星、气体和黝黑尘埃构成、近乎垂直指向的环之外，还有另一个类似但较短、斜向左上方伸展的环。极环星系到底如何获得这种引人注目的外观，目前仍然是研究的课题，但主流的理论认为，它们通常是由2个具有不同中心环指向的星系互撞而成。位于双鱼座方向，直径约50,000光年的NGC 660，距离地球约4,000万光年远。这幅主题影像，是在不久前摄于智利的El Sauce天文台。

明日的图片: open space

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