也被称作阿贝尔21，水母星云是双子座中一个1500光年远的年老行星状星云。

Also known as Abell 21, this Medusa is an old planetary nebula some 1, 500 light-years away in the constellation Gemini.

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也被称作阿贝尔21，水母星云是双子座中一个1500光年远的年老行星状星云。

Also known as Abell 21, this Medusa is an old planetary nebula some 1, 500 light-years away in the constellation Gemini.

youdao