Simeis 147: supernova remnant Simply put, a supernova is an energetic stellar explosion. SN 1006: supernova remnant The core of a star is constantly contracting, heating up and consuming lighter elements A larger star will have enough mass to compress its core and rise in temperature Massive stars with ten times more mass than the sun will be able to burn heavier elements Its weight crushes the core into its self, making it smaller and smaller If, while burning its last bit of fuel, a star is still just a bit too chubby to meet the Chandrasekhar limit, the star collapses Then, we get… Crab Nebula Massive stars have iron cores, having developed them during their stages of life Energy cannot be produced from the iron core and the massive star can no longer sustain itself The iron core begins to collapse from gravity The temperature rises, causing the iron to break apart This lessens the heat but lowers the gas pressure and speeds up the collapse Electron and protons are combined during this process and form neutrons, which releases particles called neutrinos The neutrinos carry more energy away from the center of the star, increasing the rate of collapse even more In some cases, the star never stops collapsing and turns into a black hole The star has stopped collapsing and is now just a mass comprised of mostly neutrons However, material is still falling towards this mass The layers of stellar material that were just collapsing are now being ejected away form the core at speeds around 10% the speed of light Vela Supernova Remnant Double Supernova Remnants DEM L316 Cassiopeia A: Supernova Remnant Divided into Type I-a, b, and c Light drop of 2-3 magnitude in a matter of 20-30 days Dims in an exponential fashion All Type I’s follow this fashion Type I-a supernovae are caused by thermonuclear explosions Type I-b contain much helium in their spectra For Type I-c, helium is either very week or missing from the spectra Divided into Type II-P, L, and b Light curves and spectra or different Type II’s are not always replicas or each other Give off less light than Type I’s Spend more time at maximum brightness and decay slower Type II-P are characterized by a constant in the luminosity after the maximum in the light curve Type II-L shows a linear decline Type II-b supernova generally has lost most of its H-rich cover due to its companion star in a binary system Astronomy Picture of the Day. <http://apod.nasa.gov/apod/> Marschall, Laurence. The Supernova Story. Princeton University Press: Princeton, New Jersey. 1988. Minkowski, R. "Supernovae and Supernova Remnants". Annual Review of Astronomy and Astrophysics. Vol 2: 247-266, Sep. 1964. Pols, Onno, et. al. "Close Binary Progenitors of Type Ib/Ic and IIb/II-L Supernovae". ASP Conference Series. Vol. 130, 1997..