7 - Stellar Evolution-II Surface abundances vs. time and mass loss time Whats at the surface Si-burning Pre-supernova structure for 15 solar-mass star surfacecore original CNO cycle 3He C,O C Ne,Mg,O Ne Mg,O OS,P,Mg,Si Si all kinds of stuff 8 Supernovae Type II (young massive stars) White Dwarfs Non-relativistic degenerate electronsRelativistic degenerate electrons Mass-Radius Relation & Chandrasekhar Mass NOTE! Massive Stars - Post-Collapse Plus Supernova Remnant (SNR) Crab Nebula (visible light - VLT)Keplers SN (X-rays - Chandra) Tychos SN (X-rays - Chandra) Cygnus Loop Veil Nebula Neutron Stars Black Holes Novae (plural of nova) Nova Cyg 1975 gas emission linesdust production Examples of spectra of novae at near IR wavelengths Supernovae Ia Accretion onto WD sends it over the Chandrasekhar Limit Animation SN Ia One problem: getting these to actually explode the right way has been a challenge. I recent years, the idea of colliding white dwarf stars in binary, or better yet, triple star systems has become much more attractive.