探索宇宙！每天一幅不同的影像或照片，并由专业天文学家的简短解释和说明，带你遨游迷人的宇宙。
2006年4月18日（农历二〇〇六年三月二十一）
http://www.phys.ncku.edu.tw/%7Ea ... ngc246_gemini_f.jpg
星云NGC 246和滨临死亡的恒星
影像提供: Gemini South GMOS, Travis Rector (Univ. Alaska)
Explanation: Appropriately nicknamed "the Skull Nebula", planetary nebula NGC 246 really does surround a dying star some 1,600 light-years away in the constellation Cetus. Expelled over a period of thousands of years, the lovely, intricate nebula is the outer atmosphere of a once sun-like star. The expanding outer atmosphere is interacting with the gas and dust in the interstellar medium, while the star itself, the fainter member of the binary star system seen at the nebula's center, is entering its final phase of evolution, hot white dwarf. Star and nebula are moving rapidly toward the top of the detailed view, as suggested by the nebula's brighter, upper, leading edge. The sharp image spans just over 2.5 light-years at the estimated distance of NGC 246 and also reveals distant background galaxies, some visible right through the nebula along the bottom.
解释：“骷髅星云”，形容行星状星云NGC 246的一个很合适的绰号，围绕着大约1600光年之外的鲸鱼座座的一颗正在死亡的恒星 。在一个数千年的时期里被驱逐出来，那美丽的，精致的星云是一颗类似太阳的恒星的外层大气。那向外扩张的大气在星际空间里与气体和尘埃相互作用，当恒星自身，星云中心那可见的双星系统里较暗的那颗，正在进入它演化的最后阶段， 逐渐成为一颗密度极大，炽热的白矮星。在这幅清晰的影像中，恒星和星云正急速地向上移动，被认为是星云更明亮，更上的，前头的方向。在NGC 246所在的距离，这幅高解析影像涵盖略大于2.5光年的区域，而在影像的底部可透视一些较遥远的背景星系。(Cetus -- 鲸鱼座; 骷髅星云 -- the Skull Nebula)
Tomorrow's picture: skyscape
D:D