| 释义 |
Orion OB association Orion OB association[ə‚rī·ən ¦ō′bē ə‚sō·shē‚ā·shən] (astronomy) A loose, gravitationally unbound grouping of hot massive stars with spectral types A, B, and O, which originated in the giant molecular clouds Orion A and Orion B, together with tens of thousands of low-mass young stars which formed from the Orion molecular clouds. |