散さん開かい星せい団だん

noun

open cluster

Astronomical term for a group of stars that formed from the same molecular cloud and are loosely gravitationally bound.

• プレアデス星せい団だんは有ゆう名めいな散さん開かい星せい団だんの一ひとつです。

  The Pleiades is one of the famous open clusters.