哈勃影像: 蝌蚪星系

2024年7月15日

The Tadpole Galaxy from Hubble
Image Credit: Hubble Legacy Archive, ESA, NASA; Processing: Harshwardhan Pathak

Explanation: Why does this galaxy have such a long tail? In this stunning vista, based on image data from the Hubble Legacy Archive, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation of the Dragon (Draco). Its eye-catching tail is about 280 thousand light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 – from right to left in this view – and was slung around behind the Tadpole by their gravitational attraction. During the close encounter, tidal forces drew out the spiral galaxy’s stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper right. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail’s star clusters forming smaller satellites of the large spiral galaxy.

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Tomorrow’s picture: interstellar mountains

哈勃影像: 蝌蚪星系
影像提供: Hubble Legacy Archive, ESA, NASA; 影像处理: Harshwardhan Pathak

说明: 这个星系为何有这么长的尾巴？在这幅用哈勃太空望远镜数据库制作出的精采影像里，遥远星系织就了美丽的背景，而主角则是备受扰动的螺旋星系Arp 188（蝌蚪星系）。这只宇宙级的蝌蚪位于北天的天龙座方向，离我们只有4亿2千万光年远。它吸睛的尾巴则长达28万光年，上头有许多庞大明亮的泛蓝星团。形成假说之一如是说：有个小而密实的星系，曾经从这片视野的右方向左方掠过Arp 188，然后被二者之间的引力甩到蝌蚪星系后方去。在靠得很近的时候，潮汐力把这个螺旋星系的恒星、云气和尘埃拉了出去，形成一条怪异但很很壮观的长尾。这个闯祸的星系，据估计位于蝌蚪星系后方约30万光年的地方，透过右上角前景旋涡臂的缝隙就能看见它的身影。就像地球上同名的动物一样，随着蝌蚪星系的年龄增长，它的尾巴很可能也会消失，而位于长尾上的这些星团，会成为这个大螺旋星系的小型伴星系。