ASTR 1P02 Lecture Notes - Lecture 9: Red Giant, Main Sequence, Strong Gravity
10 Apr 2016
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Document Summary
Strong gravity near a dense white dwarf atracts some of the material from companion star and the mass of the white dwarf increases. Once its mass gets close to the chandrasekhar limit (at 1. 38m ) the temperature is so high that there are runaway fusion reacions. So much energy is released that the enire system is disrupted in a giganic explosion (type ia supernova) Note: there are no hydrogen spectral lines in the spectrum of type ia supernova. Because of their high luminosity they are easy to see at very large distances. Since they all occur via the same mechanism and we know how much it explodes (the. Chandrasekhar limiing mass) they all have the same luminosity (l). This method is used to ind the distances of the most distant galaxies. The life story of a high mass star (m 8m ) Because of the high mass all stages last a shorter period of ime.
