参宿七和女巫头星云
(原标题: Rigel and the Witch Head Nebula)
2022-01-24
浏览次数: 16
在星光的照耀下，这张怪异的脸在黑暗中闪耀，弯曲的轮廓让人想起它的通俗名字——女巫头星云。事实上，这张引人入胜的望远镜照片给人的印象是女巫凝视着猎户座明亮的超巨星参宿七。女巫头星云的正式名称是IC 2118，它的跨度约为50光年，由反射参宿七星光的星际尘埃颗粒组成。女巫头星云和参宿七周围尘埃的蓝色不仅是由参宿七强烈的蓝色星光造成的，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。参宿七，女巫头星云，以及周围的气体和尘埃距离我们大约800光年远。
查看原文解释
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.
© José Mtanous