AST201H1 Lecture Notes - Helium Flash, Low Mass, Thermostat
15 Mar 2013
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AST201H1 Full Course Notes
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As it shrinks, it concentrates its energy, it heats up. Spins faster and faster, flattening out into a disk shape, called protostar( process of becoming a star) They activate bipolar jets, funneled towards mag. Black ovals are dust, fuzzy background is the orion nebula itself. Face on- jet coming towards you, so cannot be seen. Pressure generated by the heat, and bgravity trying to crush it- in equilibrium. Categories based on how thet die: low mass- less than 8m, high mass- more than 8m. Low mass- end result is white dwarf, plus a planetary nebula. Right now, 5 billion years is 80 90 % is helium. By 10 billion years, most of the core is helium. When fusion rates slow down a lot, you destroy the solar thermostat, it cannot have fusion anymore, so gravity wins. As it contracts, it releases gravitational potential energy, giving the sun a bit of reprieve, until it dies.
