IC 2118：女巫头星云
(原标题: IC 2118: The Witch Head Nebula)
2023-10-04
浏览次数: 14
这个星云看起来像女巫的头吗？这个星云通常被称为女巫头星云，因为据说，这个星云的形状类似于万圣节风格的女巫头漫画。然而，究竟如何做到这一点，可能是一个充满想象力的猜测话题。可以确定的是，IC 2118直径约50光年，由气体和尘埃组成，它指向附近的恒星参宿七，因为它已经被部分侵蚀了。参宿七是猎户座中较亮的恒星之一，位于这张特色图片的下方。女巫头星云的蓝色不仅是由参宿七强烈的蓝色星光引起的，而且因为尘埃颗粒比红光更有效地散射蓝光。同样的物理过程导致地球白天的天空呈现蓝色，尽管地球大气中的散射物是氮和氧分子。
查看原文解释
Does this nebula look like the head of a witch? The nebula is known popularly as the Witch Head Nebula because, it is said, the nebula's shape resembles a Halloween-style caricature of a witch's head. Exactly how, though, can be a topic of imaginative speculation. What is clear is that IC 2118 is about 50 light-years across and made of gas and dust that points to -- because it has been partly eroded by -- the nearby star Rigel. One of the brighter stars in the constellation Orion, Rigel lies below the bottom of the featured image. The blue color of the Witch Head Nebula and is caused not only by Rigel's intense blue starlight but because the dust grains scatter blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in planet Earth's atmosphere are molecules of nitrogen and oxygen.
© Abdullah Alharbi