行星状星云Abell 7
(原标题: Planetary Nebula Abell 7)
2025-03-07
浏览次数: 47
非常微弱的行星状星云Abell 7距离我们大约1800光年。它位于猎户座的南面，在地球的天空中，朝向熊座。在这张深望远镜拍摄的图像中，它被银河系的恒星包围，靠近遥远的背景星系的视线，它的直径约为8光年，通常是简单的球形。然而，在宇宙云内部是美丽而复杂的结构，通过使用长时间曝光和窄带滤光片来捕捉氢、硫和氧原子的发射，这些结构得以增强。否则，阿贝尔7号就会太微弱而无法被肉眼看到。行星状星云代表了恒星演化的一个非常短暂的最后阶段，我们的太阳将在50亿年后经历这个阶段，因为星云的中心，曾经像太阳一样的恒星摆脱了它的外层。据估计，Abell 7已经有2万年的历史了。但它的中心恒星，在这里看到的是一颗褪色的白矮星，大约有100亿年的历史。
查看原文解释
Very faint planetary nebula Abell 7 is about 1,800 light-years distant. It lies just south of Orion in planet Earth's skies toward the constellation Lepus, The Hare. Surrounded by Milky Way stars and near the line-of-sight to distant background galaxies its generally simple spherical shape, about 8 light-years in diameter, is revealed in this deep telescopic image. Within the cosmic cloud are beautiful and complex structures though, enhanced by the use of long exposures and narrowband filters that capture emission from hydrogen, sulfur, and oxygen atoms. Otherwise Abell 7 would be much too faint to be appreciated by eye. A planetary nebula represents a very brief final phase in stellar evolution that our own Sun will experience 5 billion years hence, as the nebula's central, once sun-like star shrugs off its outer layers. Abell 7 itself is estimated to be 20,000 years old. But its central star, seen here as a fading white dwarf, is some 10 billion years old.
© Vikas Chander