The reason is a fundamental one associated with the mechanism of light emission. 其基本原因涉及到光發(fā)射的機理。
The blue regions show the cool optical emission, detected by Hubble, from the dust and gas thrown off the star. 藍色部分表示寒冷的光發(fā)射,由哈勃探測到,來(lái)自擺脫恒星的塵埃和氣體。