AST-1A Chapter Notes - Chapter 13: Protostar, Solar Wind, Low Mass
Document Summary
Gravity it not strong enough o overcome the internal pressure of interstellar gas which is everywhere. 2 things help gravity win out over pressure: Molecular clouds: coldest and densest clouds and allow atoms to combine and form molecules tend to be quite large. Can give birth to many stars at once. Contract and produce protostar at their centre. Shrinking cloud fragments heat up as they contract which is the source of gravitational potential energy. Growing density makes it increasingly difficult for radiation to escape. Protostar: the clump of gas that will become a new star. Rotation of a shrinking cloud fragment produces a spinning disk of gas around the protostar. Planets may form later on in the disk. Young protostars fire high speed streams of gas, or jets into interstellar space. Generally see 2 jets shooting out in opposite directions.
