ASTRON 100 Lecture Notes - Lecture 15: Protostar, Red Giant, White Dwarf

• School: UMASS-Amherst
• Department: Astronomy
• Course: ASTRON 100
• Professor: Wilson Grant

Document Summary

Common properties of stars: all stars are made up of the same elements, in roughly the same proportions (including our sun, hydrogen ~70, helium ~28, other elements ~2, all stars have nuclear fusion going on in their core. Four principal characteristics of a star: luminosity, surface temperature, size, mass. Everything about a star is determined by its mass. Because it"s just a big ball of gas. How do you weigh a star: mass is the single most important property in how a star"s life and death will proceed, we can weigh stars that are in binary systems (two stars orbiting each other) Fortunately, most stars fall into this category: most stars in binary systems have a mass that is very close to its companion"s. The simple form of the law (p^2 = a^3) is correct only for objects in our solar system orbiting our sun.