虽然行星状星云阶段持续约1万年，天文学家估计其外晕的丝状物质年龄在5万至9万年间。
While the planetary nebula phase is thought to last for around 10, 000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50, 000 to 90, 000 years.
因为在仅仅数百万年之后，疏散星团开始消散，可能因为这个星团异常的年老，其内的一颗恒星已经演变到了行星状星云阶段。
Since open star clusters disperse after only a few hundred million years, this one must be exceptionally old to have one of its member stars evolve to the planetary nebula stage.
冰寒的回飞棒星云会发光，是因为它尘埃反射了来自中心星的星光，天文学家认为它是正在演化到行星状星云阶段的恒星或恒星系统。
Shining with light from the central star reflected by dust, the frigid Boomerang Nebula is believed to be a star or stellar system evolving toward the planetary nebula phase.
这个阶段的星云大小与其质量成反比。
The size of the nebula at this stage is inversely proportional to its mass.
当然，天文学家在观察“猫眼”时，就可能也看到了我们的太阳的命运，它最终注定会进入行星星云的演化阶段……
Of course, gazing into the Cat's Eye, astronomers may well be seeing the fate of our sun, destined to enter its own planetary nebula phase of evolution ...
三叶星云本身代表着恒星形成的最后阶段。
The Trifid Nebula itself represents the final phase of star formation.
行星状星云是类太阳恒星在其生命最后阶段形成的，50亿年后太阳核燃料耗尽时也将面临这样的命运。
Planetary nebulae are produced during a final phase in the life of a sun-like star, an example of the fate that awaits the sun when it runs out of nuclear fuel in another 5 billion years.
在仅仅的几千年里，星云将消散在太空中，中心的恒星将完全冷却下来，最后变成白矮星，这是几乎所有恒星演化的最后阶段。
In only a few thousand years the nebula will dissipate into space. The central star will then gradually cool down, eventually becoming a White Dwarf, the final stage of evolution for nearly all stars.
马头星云底部里的亮点，是来自正在新生阶段的年轻恒星。
Bright spots in the Horsehead Nebula's base are young stars just in the process of forming.
马头星云底部里的亮点，是来自正在新生阶段的年轻恒星。
Bright spots in the Horsehead Nebula's base are young stars just in the process of forming.
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