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Recycling Cassiopeia A Image Credit: X-ray - NASA, CXC, SAO; Optical - NASA,STScI Explanation: Massive stars in our Milky Way Galaxy live spectacular lives. Collapsing from vast cosmic clouds, their nuclear furnaces ignite and create heavy elements in their cores. After a few million years, the enriched material is blasted back into interstellar space where star formation can begin anew. The expanding debris cloud known as Cassiopeia A is an example of this final phase of the stellar life cycle. Light from the explosion which created this supernova remnant would have been first seen in planet Earth's sky about 350 years ago, although it took that light about 11,000 years to reach us. This false-color image, composed of X-ray and optical image data from the Chandra X-ray Observatory and Hubble Space Telescope, shows the still hot filaments and knots in the remnant. It spans about 30 light-years at the estimated distance of Cassiopeia A. High-energy X-ray emission from specific elements has been color coded, silicon in red, sulfur in yellow, calcium in green and iron in purple, to help astronomers explore the recycling of our galaxy's star stuff. Still expanding, the outer blast wave is seen in blue hues. The bright speck near the center is a neutron star, the incredibly dense, collapsed remains of the massive stellar core. 回收仙后座A 我们银河系的大质量恒星都会经历绚烂多彩的一生，它们从庞大的宇宙云坍塌中诞生，当内部的核熔炉点燃后，就在不停地产生重元素。数百万年后，恒星内部大量物质被抛回星际空间，成为下一代恒星形成的材料。这幅图像中不断扩张的碎片云被称为仙后座A，是恒星生命周期最后阶段的一个实例。虽然产生这个超新星遗迹的爆炸闪光大约在350年前首次出现在地球的天空中，但是它需要经过约11,000年才传到这里。这幅图像由钱德拉X射线天文台的图像数据和哈勃太空望远镜的光学影像数据结合而成，呈现了超新星遗迹中仍然炽热的丝状结构和物质结。以仙后座A的距离计算，它的跨度约为30光年。我们对特定元素发出的高能X射线进行了颜色编码，红色代表硅元素，黄色代表硫元素，绿色代表钙元素，紫色代表铁元素，这可以帮助天文学家探索我们银河系中恒星物质是如何回收的。仍在扩张的外层冲击波呈现出蓝色色泽。图像中心附近的亮斑是一颗中子星，是大质量恒星核塌缩后留下的极其致密的残骸。 高清原图地址： https://apod./apod/image/1909/Chandrafirstlight_0.jpg 近期文章： Astronomy Picture of the Day——“天涯海角” Astronomy Picture of the Day——大麦哲伦星系 Astronomy Picture of the Day——蜘蛛星云的红外影像 NASA 微店 |
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