2018年07月08日:飞马座LL星的不寻常螺旋结构-（The Extraordinary Spiral in LL Pegasi）

2018年07月08日:飞马座LL星的不寻常螺旋结构-（The Extraordinary Spiral in LL Pegasi）--原图下载

Image Credit: NASA, ESA, Hubble, HLA;Processing & Copyright: Domingo Pestana &Raul Villaverde
说明: 影像左侧的螺旋结构是怎么产生的？ 没人能给个明确的答案，不过它可能是一颗在双星系统里的恒星，抛出外层的大气因而进入到行星状星云阶段有关。 这个横跨了3分之1光年、并且缠绕了4到5圈之多的庞大螺旋 ，其完整迴圈的规律性前所未见。 以这团螺旋气体的扩散速率来推算，大约每8百年会产生一个新层，和这与两颗恒星互绕的週期相当接近。 产生这个结构的恒星系统常见的名称为飞马座LL星，亦称为AFGL 3068；而这个不寻常的结构，则拥有IRAS 23166+1655的编录号。这张主题影像，是由哈伯太空望远镜摄于近红外光波段。这个螺旋结构为何会发光也颇让人困惑，最可信的假说指出那是因为它反射了附近恒星的星光。

原文：

Image Credit: NASA, ESA, Hubble, HLA;Processing & Copyright: Domingo Pestana &Raul Villaverde
Explanation: What created the strange spiral structure on the upper left? No one is sure, although it is likely related to a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected. The huge spiral spans about a third of a light year across and, winding four or five complete turns, has a regularity that is without precedent. Given the expansion rate of the spiral gas, a new layer must appear about every 800 years, a close match to the time it takes for the two stars to orbit each other.The star system that created it is most commonly known as LL Pegasi, but also AFGL 3068. The unusual structure itself has been cataloged as IRAS 23166+1655.The featured image was taken in near-infrared light by the Hubble Space Telescope.Why the spiral glows is itself a mystery, with a leading hypothesis being illumination by light reflected from nearby stars.