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.

当我们的星云在自身重力作用下崩溃和更加快速地旋转时，星云成了集的。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.

部分的重力能量在崩溃的过程会以红外线的式损失掉，其馀的则会用于增加天体核的温度。