2026年2月13日
NGC 147 and NGC 185
Image Credit & Copyright: Chuck Ayoub
Explanation: Dwarf galaxies NGC 147 (left) and NGC 185 stand side by side in this deep telescopic portrait. The two are not-often-imaged satellite galaxies of M31, the great spiral Andromeda Galaxy, some 2.5 million light-years away. Their separation on the sky, less than one degree across a pretty field of view toward the constellation Cassiopeia, translates to only about 35 thousand light-years at Andromeda’s distance, but Andromeda itself is found well outside this frame. Brighter and more famous satellite galaxies of Andromeda, M32 and M110, are seen much closer to the great spiral. NGC 147 and NGC 185 have been identified as binary galaxies, forming a gravitationally stable binary system. But recently discovered faint dwarf galaxy Cassiopeia II also seems to be part of their system, forming a gravitationally bound group within Andromeda’s intriguing population of small satellite galaxies.
Tomorrow’s picture: floral arrangement
NGC 147与NGC 185
影像提供与版权: Chuck Ayoub
解说: 在这张深空望远镜拍摄的照片中，矮星系NGC 147（左）和NGC 185并肩而立。这两个星系者是M31-巨大的螺旋星系仙女座星系-较少被拍摄到的卫星星系，距离我们约250万光年。它们在天空中的角距离不到1度，位于仙后座方向的一片优美视场，换算成仙女座星系的距离，大约只有3.5万光年，但仙女座星系本身位于这幅图像之外。更明亮且更知名的仙女座卫星星系，如M32与M110，则离仙女座星系更近。NGC 147与NGC 185已被确认为双星系，构成一个引力稳定的双星系系统。而最近发现的暗淡矮星系仙后座II（Cassiopeia II）似乎也属于此系统的一员，与它们共同形成一个重力束缚的小型群体，存在于仙女座丰富而耐人寻味的矮质量卫星星系族群之中。
明日的图片: floral arrangement
