Protostels

Protostars are the earliest stage in the formation of a star. They are dense cores of gas and dust within molecular clouds, which are the birthplaces of stars. These cores are typically a few thousand astronomical units in size and have masses ranging from a few to several hundred solar masses. The process of protostar formation begins when a molecular cloud begins to collapse under its own gravity, leading to the concentration of mass in the core. As the core collapses, it heats up due to the conversion of gravitational potential energy into thermal energy. This heating causes the core to become opaque to its own radiation, leading to a further increase in temperature and pressure. The central region of the collapsing core eventually becomes hot and dense enough to initiate nuclear fusion, marking the birth of a main-sequence star. The remaining material from the molecular cloud may form planets, asteroids, and other celestial bodies. Protostars are often surrounded by accretion disks, which are rotating disks of gas and dust that feed material onto the protostar. These disks can also give rise to the formation of planetary systems. The study of protostars provides valuable insights into the processes of star and planet formation, as well as the evolution of the universe.