ASTR 1P02 Lecture Notes - Lecture 3: Low Mass, Star System, Brown Dwarf
14 Mar 2016
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Document Summary
Once a star reaches the main sequence stage, its further evoluion depends on its mass. If the mass of the contracing clump is less than 1/12 the mass of the sun=0. 08 mass of the sun, its core never gets hot enough to fuse hydrogen into helium (never reaches the main sequence stage) Brown dwarfs are formed if it doesn"t get hot enough (planet jupiter is an example of a brown dwarf) M = solar mass (mass of the sun) Hydrogen is fused into helium through the proton-proton chain: The net result is: (6-2)=4 protons are fused into the nucleus of 4^he, with release of energy. The mass of 4^he is slightly smaller than the mass of four protons used to make it m=4 m of. Because of their low mass their luminosity is low (l=m^3. 5) and they are at the botom of the main sequence (dim and cool stars)
