[2017年10月02日:彗星与星团-（Two Comets and a Star Cluster）--原图下载](https://apod.nasa.gov/apod/image/1710/PleiadesComets_Peach_2081.jpg"
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Image Credit &Copyright: Damian Peach
说明: 二个不寻常光斑在着名的昴宿星团附近移动。这些每一晚只偏移一点点的光斑，其实是我们太阳系内围的彗星，恰好通过远在光年之遥的恒星前方。位在影像左缘的是彗星C/2017 O1 ASAS-SN，它是一团蒸发中宽达数公里的冰块，拥有主要受碳泛绿辐射渲染的气体彗发。而在彗星ASAS-SN1的右下方，可见到一道短短的彗尾。位在影像中央附近的是彗星C/2015 ER61 PanSTARRS，它除了也是一大团蒸发中的冰块之外，右侧更带着一道相当长的彗尾。影像右上角的昴宿星团，是一个由照亮邻近反射尘埃的泛蓝亮星聚成的疏散星团。这幅摄于2星期前的影像是如此深邃，所以整个视野里到处都是丝缕状的星际尘埃。昴宿星团是肉眼可见的天体，不过要透过双筒望远镜才看得到这二颗彗星。
原文：
Image Credit &Copyright: Damian Peach
Explanation: Two unusual spots are on the move near the famous Pleiades star cluster.Shifting only a small amount per night, these spots are actually comets in our nearby Solar System that by chance wandered into the field of the light-years distant stars. On the far left is comet C/2017 O1 ASAS-SN, a multi-kilometer block of evaporating ice sporting a bright coma of surrounding gas dominated by green-glowing carbon. Comet ASAS-SN1 shows a slight tail to its lower right. Near the frame center is comet C/2015 ER61 PanSTARRS, also a giant block of evaporating ice, but sporting a ratherlong tail to its right.On the upper right is the Pleiades, an open cluster dominated by bright blue stars illuminating nearby reflecting dust. This exposure, taken about two weeks ago, is so deep that the filamentary interstellar dust can be traced across the entire field.The Pleiades is visible to the unaided eye, but it should require binoculars to see the comets.
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