As our nebula began to collapse under its own gravity and spin faster, a dense clump of matter formed in the center. It's called a protostar.

当我们的星云自身重力作溃和更加快速地旋转时，星云中心形成了集的物质块。这叫做原恒星。

As described above, the collapse of a rotating cloud of gas and dust leads to the formation of an accretion disk through which matter is channeled onto a central protostar.

部分的重力能溃的过程中会以红外线的形式损失掉，其馀的则会于增加天体核心的温度。