Astronomy Picture of the Day——Arp 188和蝌蚪尾巴
Arp 188 and the Tadpole's Tail
Image Credit: Hubble Legacy Archive, ESA,NASA; Processing: Faus Márquez
Explanation: Why does this galaxy have sucha long tail? In this stunning vista, based on image data from the Hubble LegacyArchive, distant galaxies form a dramatic backdrop for disrupted spiral galaxyArp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 millionlight-years distant toward the northern constellation of the Dragon (Draco).Its eye-catching tail is about 280 thousand light-years long and featuresmassive, bright blue star clusters. One story goes that a more compact intrudergalaxy crossed in front of Arp 188 - from right to left in this view - and wasslung around behind the Tadpole by their gravitational attraction. During theclose encounter, tidal forces drew out the spiral galaxy's stars, gas, and dustforming the spectacular tail. The intruder galaxy itself, estimated to lieabout 300 thousand light-years behind the Tadpole, can be seen throughforeground 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 starclusters forming smaller satellites of the large spiral galaxy.
Arp 188和蝌蚪尾巴
为什么这个星系有这么长的尾巴？这幅迷人的远景图像是由哈勃遗珍档案的影像数据构建的，图中呈现的遥远星系是遭受侵扰、被称为蝌蚪星系的旋涡星系Arp 188。这只宇宙蝌蚪位于朝向北天的天龙座方向，距离我们只有不到4亿2千万光年。它最引人注目的尾巴约有28万光年长，镶嵌着许多明亮的大质量蓝色星团。有一则假说是，一个较致密的星系从影像右侧向左侧掠过Arp 188前方，然后被蝌蚪星系的引力抛甩到其后方。在近距离碰撞时，潮汐力将该旋涡星系的恒星、气体和尘埃拉拽出来，形成了壮观的尾巴。据估计，这个入侵星系位于蝌蚪星系后方约30万光年处，可以透过右上方的前景旋臂看到它。如同地球上的青蛙幼子一样，随着蝌蚪星系年龄的增长，它的尾巴很可能会消失，而尾巴上的星团则会成为庞大旋涡星系的小型卫星们。
参考文献：
https://apod.nasa.gov/apod/image/1812/Arp188Tadpole_HubbleMarquez_1150.jpg
近期文章：
Astronomy Picture of the Day——M95：带内环的旋涡星系