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.
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