protostar

例句：

1. 1. The protostar is a tiny star that is still forming.
   这个原恒星是一个仍在形成的微小恒星。
2. 2.The discovery of protostars in the early universe has revolutionized our understanding of the origins of the cosmos.
   在早期宇宙中发现原恒星已经彻底改变了我们对宇宙起源的理解。
3. 3. Astronomers have been studying protostars for decades, trying to understand their formation and evolution.
   天文学家们已经研究原恒星几十年了，试图理解它们的形成和演化过程。