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Name: Maya My Deep Space Mystery Topic: Parts of Your Lesson Title Introduction Subtopic 1 Subtopic 2 What I’ll See Supernovae! What is a supernova? Supernovae What I’ll Hear Explosion sound effect A supernova is a relatively rare event in our galaxy, it happens about every 50 to I00 years. A supernova is a stellar explosion that happens as a result of the death of a massive star. It involves the expulsion of the star’s outer layers and the eventual explosion of the star itself. When a supernova explodes, briefly it can outshine an entire galaxy, and give out as much energy as the sun will in a life- time, and the explosion is equivalent to the power in a I0II8 megaton bomb (i.e., a few octillion nuclear warheads). The explosion also fills the space around it with clouds of gas, debris and dust. Sometimes a solar nebula can form from the remains of the supernova. How do supernova Supernovae occur when the occur? star’s core fusion process runs out of fuel. The outward pressure drops, causing the gravitational pull to become unbalanced. The core starts to condense under gravity because there is a lack of outward pressure. When the core shrinks too much, iron atoms are crushed together, temperatures reach billions of degrees Celsius, the star swells and grows and finally a series of nuclear reactions is unleashed. The supernova produces a giant shock wave that throws matter into space at 9,000 to II5,000 miles per second. Type Ia, Ib and Ic There are two major classes of Supernovae Subtopic 3 Type II Supernova supernovae, type I and type II. Out the window is a example of Ia supernova. Lets get a closer look. Type I supernova contain hydrogen in their spectrum, but Type II do not. Type I supernovae have several divisions, type Ia, Ib and Ic. Type Ia does not contain helium, but do have a silicon line in their spectrum. They are thought to be formed in some binary star systems and are created by the explosion of a carbon oxygen white dwarf. The type Ia supernova is caused when the density of the white dwarf reaches II x I09 g/cm and the dwarf collapses into a neutron star or black hole. The collapse causes the carbon and oxygen atoms to fuse. This fusion produces the supernova’s shockwave and the dwarf star is blown apart. Type Ib and Ic supernovae contain helium in their spectrum, but do not have the silicon line that appears in type Ia supernovae. Type Ib is thought to be formed when a massive star that is made mainly of helium, carbon, nitrogen or oxygen collapses, also called a Wolf-Rayet star. The type II supernova occurs at the end of a star’s life when the nuclear fuel of the star runs out. Out the window is type II supernova. Again lets get a closer look. If the star’s iron core is massive enough, when it collapses, it will explode in a supernova. Some scientists think that type Ib supernovae are actually type II. The hydrogen was probably blown away by the huge star’s strong stellar winds before the star exploded which explains the lack of hydrogen in its spectrum. Subtopic 4 Black Holes and Neutron Stars Subtopic 5 Observation History When the supernova is done exploding, as an effect of the large transfer of matter and energy, there is a very different kind of star left. This star is called a spinning neutron star. Neutron stars produce radio waves in a steady stream or in random bursts. But if a star is massive enough, it can leave behind something more. For this to happen though, the star must be at least I0 times the size of the sun. When these stars explode, their supernova leaves a large core, and with no energy to fuse it doesn’t have any outward pressure, and that causes it to be very unbalanced. The star gets engulfed in its own gravity and becomes a black hole, as you can see out the window. Supernovae occur in our galaxy about every 50 - 100 years, however, several hundred are observed every year in other nearby galaxies. On earth, supernovae can be seen for weeks in the sky. The first supernova recorded was in I85 AD, called SN I85. It was recorded by Chinese Astronomers and was in the sky for 8 months. Some important supernovae that have happened over the years are Kepler’s Supernova in I604, the supernovae that produced the Crab Nebula in I054, and the one that happened in the Large Effects Resources April 14, 2011Supernova http://en.wikipedi a.org/wiki/Superno va#Observation_his tory April 14th 2011 Supernovae http://science.nat ionalgeographic.co m/science/space/un iverse/supernovaearticle.html April 14th 2011 Supernovae http://science.nat ionalgeographic.co m/science/space/un iverse/supernovaearticle.html Magellanic Cloud in I987. Supernovae place a lot of the heavy elements and a lot of other material in our universe. When a supernova occurs, the remnants of the original star remain. These remnants are what heat up the gases and dusts between the stars, they also help new stars form, and they add elements to space clouds. Iron that is found in supernovae made our planet and even ourselves. Supernova are amazing to learn about. They are beautiful to see and the have effected the development of our universe. With all the great things about supernova, it may surprise you to learn that unfortunately, some people think that a supernova will destroy our solar system. ☹