ASTRON 1101 Lecture Notes - Lecture 19: Ideal Gas Law, Hydrostatic Equilibrium, Horse Length
11 Oct 2016
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Document Summary
The main sequence: main sequence stars range in mass from 0. 008 msun for the dimmest red dwarfs to ~100. Msun for the brightest o stars: main sequence stars gradually become more luminous, as their central temperature slowly increase, the nuclear timescale of a main sequence star is inversely proportional to the cube of its mass. Main sequence stars lie on a narrow diagonal band on the h-r diagram. The main sequence is a mass sequence: although a few more luminous main sequence stars exist, they are extremely rare, remember, this is the temperature of the photosphere at the star"s surface. The lowest mass main sequence stars have a mass m = 0. 08 msun. These are red dwarfs of spectral types m that have l = 10-4 lsun, t = 3000k, r = 0. 1 rsun. Smaller balls of gas aren"t hot enough in their core to fuse hydrogen into helium.
