180115期:参宿七和女巫头星云

参宿七和女巫头星云

在星光下,这张诡异的脸在黑暗中闪耀,扭曲的轮廓让人想起了它的名字——女巫头星云。事实上,这幅引人注目的望远镜照片给人的印象是,女巫将目光锁定在猎户座明亮的超巨星参宿七上。正式编号为IC 2118,女巫头星云跨度约50光年,由反射了星宿七光亮的星际尘埃组成。女巫头星云和围绕着参宿七泛蓝色尘埃不仅是由参宿七的强烈的蓝色星光造成的,还因为尘埃颗粒比红色更有效地散射蓝光。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粒子是氮气和氧气分子。参宿七,女巫头星云以及周围的气体和尘埃距离我们大概800光年。

:银河说翻译组岑

Rigel and the Witch Head Nebula 
Image Credit & Copyright: Mario Cogo (Galax Lux)

Explanation: By starlight this eerie visage shines in the dark, a crooked profile evoking its popular name, the Witch Head Nebula. In fact, this entrancing telescopic portrait gives the impression that the witch has fixed her gaze on Orion’s bright supergiant star Rigel. More formally known as IC 2118, the Witch Head Nebula spans about 50 light-years and is composed of interstellar dust grains reflecting Rigel’s starlight. The blue color of the Witch Head Nebula and of the dust surrounding Rigel 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 Earth’s atmosphere are molecules of nitrogen and oxygen. Rigel, the Witch Head Nebula, and gas and dust that surrounds them lie about 800 light-years away.

 

 

 

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