2025年4月24日
NGC 6164: A Dragon’s Egg
Image Credit & Copyright: Daniel Stern
Explanation: Beautiful emission nebula NGC 6164 was created by a rare, hot, luminous O-type star, some 40 times as massive as the Sun. Seen at the center of the cosmic cloud, the star is a mere 3 to 4 million years old. In another three to four million years the massive star will end its life in a supernova explosion. Spanning around 4 light-years, the nebula itself has a bipolar symmetry. That makes it similar in appearance to more common and familiar planetary nebulae – the gaseous shrouds surrounding dying sun-like stars. Also like many planetary nebulae, NGC 6164 has been found to have an extensive, faint halo, revealed in this deep image of the region. Expanding into the surrounding interstellar medium, the material in the halo is likely from an earlier active phase of the O star. This gorgeous telescopic view is a composite of extensive narrow-band image data, highlighting glowing atomic hydrogen gas in red and oxygen in greenish hues, with broad-band data for the surrounding starfield. Also known as the Dragon’s Egg nebula, NGC 6164 is 4,200 light-years away in the right-angled southern constellation of Norma.
Tomorrow’s picture: Lucy in the sky
NGC 6164: 龙蛋星云
影像提供与版权: Daniel Stern
说明: 美丽的发射星云NGC 6164，是由一颗质量约为40倍太阳的稀有、炽热明亮O型星所产生的。位于这团星云中心的这颗恒星，稚龄仅有3到4百万年的。不过，只要再过3到4百万年，这颗大质量恒星会以超新星爆炸的形式结束它的生命。宽度约为4光年的这团星云，具有双极瓣对称性，因此其外观类似较常见、由垂死类太阳恒星外层气壳所形成的行星状星云。而且与许多行星状星云类似，NGC 6164 也拥有庞大且昏暗的外晕，如上面这幅呈现此天区的深空望远镜影像所示。持续往周围星际介质扩张的外晕物质，则可能是O型星在活跃的早期阶段所排出的。这幅壮丽的望远镜影像，整合了呈现周围星场的宽波段数据，并组合大量的窄波段影像数据，以突显氢原子气体发出的红光辐射及氧原子的泛绿辐射。有龙蛋星云之称的NGC 6164，位于南天以木匠角尺为名的矩尺座方向约4,200光年远之处。
明日的图片: Lucy in the sky
