Supernova High-mass star’s final brilliance Star explodes A turning off or sudden turn on of nuclear fusion
Classifying Type I & Type II ◦ Type I doesn’t have hydrogen Type Ia, Ib, Ic ◦ Type Ia Exploded white dwarf ◦ Type Ib & Ic Massive stars that have blown away outer layers Doesn’t have a silicon line like type Ia
Implications Similar compositions, same mass Practically same brightness Can measure distances Observed Brightness = Luminosity 4π*Distance 2 Standard candle
The Universe’s Accelerating Expansion Observe supernova Determine distance Results are farther away, and receding faster than expected in a universe expanding at a constant rate Conclude accelerating expansion
Core Collapse Super massive star at the end of its lifetime Star has layers of fused chemical elements up to iron Iron does not fuse so the core can’t generate heat. Once the core reaches the Chandrasekhar mass, the core pressure drops and overlying material falls in.
More Core Collapse The core collapses and material bounces off the core, resulting in a shock wave Neutrino pulse propels shock wave Shock wave blows star apart
Type Ib & Ic Supernovae Type II supernovae Type Ib supernovae ◦ Blown off hydrogen shell Type Ic supernovae ◦ Blown off hydrogen and helium shells
Visualizing Type Ib & Ic Supernovae Type Ib (SN 2005bf)Type Ic (SN 2006jc)
Works Referenced Bennett, Jeffrey, Megan Donahue, Nicholas Schneider, and Mark Voit. The Cosmic Perspective. 3rd ed. Boston: Addison Wesley, 2004. "Dark Energy." ChemistryDaily.com. 01 Jan 2007. 27 Nov 2007. Goldhaber, Gerson and Saul Perlmutter. "A study of 42 type Ia supernovae and a resulting measurement of Ω M and ΩΛ." Physics Reports 307.1-4. 01 Dec 1998 325-331. 27 Nov 2007. Hillebrandt, Wolfgang, Hans-Thomas Janka, and Ewald Müller. "How to Blow Up a Star." Scientific American Oct. 2006: 43-49. Leibundgut, Bruno and Jesper Sollerman. "A cosmological surprise: the universe accelerates." Europhysics News 32.4. 2001 27 Nov 2007. "Supernova." wikipedia.org. 27 Nov 2007. Wikimedia Foundation, Inc.. 27 Nov 2007. "Type Ia Supernova." wikipedia.org. 25 Nov 2007. Wikimedia Foundation, Inc.. 27 Nov 2007. Van Dyk, Schuyler D.. "ASTRONOMY: Elusive Supernova Progenitors." Science 302.5648. 14 Nov 2003 1161-1162. 27 Nov 2007. Wawrzyn, Alexander. "Modeling Supernovae with PHOENIX." www.hs.uni-hamburg.de. 05 Sep 2006. Universität Hamburg. 27 Nov 2007.