Whirling , swirling , circumstellar cloud of dust and gas gave birth to the earth , or so astrophysicists have long believed 一团尘埃和气体绕着太阳不断旋转并形成旋涡，接着地球诞生了? ?至少天体物理学家们长期以来都是这样认为的。
3.
Another expectation , which hubble overturned , was that the circumstellar disks would be deeply embedded within their parent clouds and would therefore be impossible to see 另外有一个被哈伯推翻的猜测，是因为环绕恒星的气盘深藏在其母云气之中，所以无从窥其究竟。
4.
Intense ultraviolet radiation from the core heats the circumstellar gas to ten thousand degrees , and the velocity of the gas flowing away from the star jumps to about a million miles per hour 核心强烈的紫外辐射将星周气体加热到上万度，从恒星流出的气体速度跃升到了每小时百万英里。
5.
By using the iso sws spectra we have studied their physical nature including their molecular and dust features in the circumstellar envelope to make us understand the evolutionary status of carbon stars 这29颗sic碳星的isosws光谱能很好地反映碳星的演化，有助于我们了解碳星的演化及其分子、尘埃特征。
6.
The infrared carbon stars , whose infrared spectra are mainly due to the dust emission in the circumstellar envelope , are usually believed to be surrounded by the carbon rich envelope characterized by the sic emission feature at 11 . 3um 红外碳星常被认为有很厚的富碳拱星壳层，它的红外光谱主要表现为源于拱星壳层的尘埃发射，这个尘埃发射主要以11 . 3 m的sic发射为标记。
