ASTR 1100 Lecture Notes - Lecture 14: Figure Skating, Molecular Cloud, Protostar
Document Summary
Mass determines the lifespan of a star. Scientists are able to figure out the stages a star goes through by taking various measurements using the new and old stars. Stars consists of 70% hydrogen, 28% helium, 2% heavier elements. Interstellar clouds collapse under their own gravity. => clouds must be cold and approximately 10kelvin for its gravity to collapse. Triggers: collision between two molecular clouds, supernova remnants collision with molecular cloud, pressure wave produced when nearby o or b stars form. The cloud contain hundreds or thousands of dense cores. Many stars sometimes have planets because of the spinning of the dense core. => conservation of angular momentum. (figure skater in a pirouette). => the dense core must have some rotation for a star to form (must be fast rotation). The core collapses gravitationally, mass increases, it shrinks and heats up protostar stage. => protostar is not a star (baby star). => the first step to forming a star.
