Under proposed international astronomical union definitions , two planets that orbit each other around a barycenter between them are a binary planet 根据国际天文学会的定义提出两个行星轨道周围的重心在彼此之间是双行星系统。
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After a tumultuous week of clashing over the essence of the cosmos , the international astronomical union stripped pluto of the planetary status it has held since its discovery in 1930 经过一周关于宇宙本质纷乱的讨论之后，国际天文学会剥夺了冥王星行星的地位，这个地位自1930年发现冥王星时起被认定。
