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.

当我们星云在自身重力作用下崩溃和更加旋转时，星云中心形成了密集物质块。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.

部分重力能量在崩溃过程中以红外线形式损失掉，其馀用于增加天体核心温度。