AST 2002 Chapter Notes - Chapter 12: Low Mass, Solar Mass, Red Giant
Document Summary
T = gas temperature in kelvin. n = gas density. Stars are formed from molecular clouds; highly dense clouds of interstellar gas made mostly of hydrogen. Observations suggest that stars form from colder and denser molecular clouds. Molecular clouds can be thousands of times larger than a typical star born from it and many clouds produce more than one star, and these are known as star clusters. These clouds undergo the process of star formation when a shift in gravity causes the mass of the cloud to sustain nuclear fusion in its center. If the cloud attains nuclear equilibrium, balancing its inner gravitation pull against the outward push of the pressure from interstellar gases, then it will begin to undergo nuclear fusion and form a star. Neither gravity nor nuclear equilibrium can always be maintained, and may explain why not every star formation is uncommon.
