ASTR 170B2 Lecture Notes - Lecture 14: White Dwarf, Big Bang, Electron Degeneracy Pressure
13 Oct 2017
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Document Summary
Luminosity: the total amount of energy a star radiates into space every second. Collapsing star to gravitational energy heating up interior and getting more luminous. Stars remain on the main sequence for as long as they can fuse hydrogen into helium in the core. Evolution of low mass stars (like the sun) Red giant-planetary nebula- helium core fusion (cools) to white warf. Fusion progresses no further in a low-mass star because the core temp never grows hot enough for fusion of heavier elements. High mass stars have short life spans and go through several additional stages of nuclear burning to produce the elements necessary for life! Early to mid life stages of high mass stars are similar to those of low mass stars: Vigorous hydrogen core fusion via cno cycle (main sequence) Helium core fusion (super giant) wont get the ash from this burning. Big bang made 75% hydrogen and 25% helium.
