1 Supernova By: Courtney Lee and Matt Tanaka

Supernova An explosion of a massive supergiant star. An explosion of a massive supergiant star. One of the most energetic explosive events. One of the most energetic explosive events. Occurs at the end of a star’s lifetime, when its nuclear fuel is exhausted and it is no longer supported by the release of nuclear energy. Occurs at the end of a star’s lifetime, when its nuclear fuel is exhausted and it is no longer supported by the release of nuclear energy. If the star is particularly massive, then its core will collapse and in so doing will release a huge amount of energy. This will cause a blast wave that ejects the star's envelope into interstellar space. If the star is particularly massive, then its core will collapse and in so doing will release a huge amount of energy. This will cause a blast wave that ejects the star's envelope into interstellar space. In a single cataclysm, a massive star may blow itself to bits, releasing as much energy, for a brief time, as an entire galaxy. In a single cataclysm, a massive star may blow itself to bits, releasing as much energy, for a brief time, as an entire galaxy.

Supernova It may shine with the brightness of 10 billion suns. It may shine with the brightness of 10 billion suns. The total energy output may be joules. The total energy output may be joules. Only seen in galaxies other than the Milky Way. Only seen in galaxies other than the Milky Way. Tycho Brahe and Johannes Kepler, discovered bright supernovae occurring in the Milky Way in 1572 and Tycho Brahe and Johannes Kepler, discovered bright supernovae occurring in the Milky Way in 1572 and no supernova has been seen in our Galaxy since Kepler's. no supernova has been seen in our Galaxy since Kepler's.

Type I Supernova The explosion and complete destruction of a dead star called a white dwarf. The explosion and complete destruction of a dead star called a white dwarf. Type I supernova can occur if the white dwarf is made of carbon and if it is a member of a binary system. Type I supernova can occur if the white dwarf is made of carbon and if it is a member of a binary system. A white dwarf cannot be more massive than about 1.4 solar masses and remain stable. A white dwarf cannot be more massive than about 1.4 solar masses and remain stable. if the white dwarf's companion star expands to become a red giant, some of its matter may be drawn away and sucked onto the surface of the white dwarf. if the white dwarf's companion star expands to become a red giant, some of its matter may be drawn away and sucked onto the surface of the white dwarf.

Type II Supernova A massive star runs out of thermonuclear fuel and can no longer sustain itself against the inward pull of its own gravity. A massive star runs out of thermonuclear fuel and can no longer sustain itself against the inward pull of its own gravity. The star collapses in a matter of seconds. The star collapses in a matter of seconds. The core is crushed into a tiny object called a neutron star, which may be no more than 6 mi (10 km) across. The core is crushed into a tiny object called a neutron star, which may be no more than 6 mi (10 km) across. The outer layers collapse as well, but when they encounter the extremely hard, rigid, collapsed core, they bounce off it. The outer layers collapse as well, but when they encounter the extremely hard, rigid, collapsed core, they bounce off it.

Identifying Each Type Astronomers can tell the type of a supernova by observing its total brightness as well as its spectrum. Astronomers can tell the type of a supernova by observing its total brightness as well as its spectrum. Type I supernova release more energy and therefore have a lower absolute magnitude. Type I supernova release more energy and therefore have a lower absolute magnitude. Type II has prominent hydrogen lines in their spectra because hydrogen is the primary element in the exploding star. Type II has prominent hydrogen lines in their spectra because hydrogen is the primary element in the exploding star.

Astronomers and sdadlSupernova Type I supernova are useful to astronomers trying to determine the distances to other galaxies. Type I supernova are useful to astronomers trying to determine the distances to other galaxies. Since all Type I supernova have about the same absolute brightness, astronomers can calculate how far away a Type I supernova is by measuring its apparent brightness and then calculating how far away it must be to appear that bright. Since all Type I supernova have about the same absolute brightness, astronomers can calculate how far away a Type I supernova is by measuring its apparent brightness and then calculating how far away it must be to appear that bright. Type I supernovae serves as one of several kinds of distance indicators that help us determine the size of the Universe. Type I supernovae serves as one of several kinds of distance indicators that help us determine the size of the Universe.

Effects When a supernova explodes, they have profound effects on their surroundings in galaxies. When a supernova explodes, they have profound effects on their surroundings in galaxies. The tremendous energy that is liberated affects the gas in its environment, pushing on it and compressing it. If the gas was originally fairly dense, then the compressed denser gas can actually go on to collapse and form new stars. The tremendous energy that is liberated affects the gas in its environment, pushing on it and compressing it. If the gas was originally fairly dense, then the compressed denser gas can actually go on to collapse and form new stars. Later generations of stars formed after the supernova contain more heavy elements than previous generations. Later generations of stars formed after the supernova contain more heavy elements than previous generations. The enrichment of the gas in our region of the Milky Way reached such a point that a sufficient quantity of heavy elements existed to give rise to life here on Earth. The enrichment of the gas in our region of the Milky Way reached such a point that a sufficient quantity of heavy elements existed to give rise to life here on Earth.

Summary A supernova is an explosion of a massive supergiant star. A supernova is an explosion of a massive supergiant star. Occurs at the end of a stars lifetime when its nuclear fuel is exhausted and is no longer supported by the release of nuclear energy. Occurs at the end of a stars lifetime when its nuclear fuel is exhausted and is no longer supported by the release of nuclear energy. The enrichment of the gas in our region of the milky way reached such a point that a sufficient quantity of elements existed to give rise to life here on earth. The enrichment of the gas in our region of the milky way reached such a point that a sufficient quantity of elements existed to give rise to life here on earth.

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