2025年8月31日
NGC 7027: The Pillow Planetary Nebula
Image Credit: NASA, ESA, Hubble; Processing: Delio Tolivia Cadrecha
Explanation: What created this unusual planetary nebula? Dubbed the Pillow Nebula and the Flying Carpet Nebula, NGC 7027 is one of the smallest, brightest, and most unusually shaped planetary nebulas known. Given its expansion rate, NGC 7027 first started expanding, as visible from Earth, about 600 years ago. For much of its history, the planetary nebula has been expelling shells, as seen in blue in the featured image by the Hubble Space Telescope. In modern times, though, for reasons unknown, it began ejecting gas and dust (seen in brown) in specific directions that created a new pattern that seems to have four corners. What lies at the nebula’s center is unknown, with one hypothesis holding it to be a close binary star system where one star sheds gas onto an erratic disk orbiting the other star. NGC 7027, about 3,000 light years away, was first discovered in 1878 and can be seen with a standard backyard telescope toward the constellation of the Swan (Cygnus).
Tomorrow’s picture: smashed moonball
NGC 7027: 枕形行星状星云
影像提供: NASA, ESA, Hubble; 影像处理: Delio Tolivia Cadrecha
说明: 这个不寻常的行星状星云是如何形成的？NGC 7027又称为枕头星云或飞毯星云的NGC 7027，是已知最小、最亮且形状最不寻常的行星状星云之一。根据其膨胀速度，从地球上看NGC 7027大约在600年前开始膨胀。在它的大部分历史中，这个行星状星云不断地喷出壳层，如哈勃太空望远镜拍摄的特色图片中的蓝色部分所示。然而在现代，由于未知原因，它开始在特定方向喷出气体和尘埃（以棕色显示），形成了一个似乎有四个角落的新图案。星云中心的物体仍然未知，有一种假设认为它是一个紧密的双星系统，其中一颗恒星将气体抛洒到环绕另一颗恒星的不稳定圆盘上。NGC 7027距离我们约3,000光年，于1878年首次被发现，并且可以用普通的后院望远镜在天鹅座（Cygnus）方向观测到。
明日的图片: smashed moonball
