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Supernova
By: Courtney Lee and Matt Tanaka
1
 An explosion of a massive
supergiant star.
Supernova
 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.
 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
Supernova
 It may shine with the brightness of 10 billion
suns.
 The total energy output may be 1044 joules.
 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 1604.
 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.
 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.
 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.
 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 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.
 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.
Astronomers and
 Type I supernova are useful
to astronomers trying to
sdadlSupernova
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.
 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.
 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.
 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.
 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.
Works Cited
 "Supernova." HEASARC: NASA's Archive of Data on
Energetic Phenomena. Web. 08 Feb. 2011.
<http://heasarc.nasa.gov/docs/snr.html>.
 "Supernovae." Test Page for Apache Installation.
Web. 08 Feb. 2011. <http://hyperphysics.phyastr.gsu.edu/hbase/astro/snovcn.html>.
 "Curious About Astronomy? Supernovae." Curious
About Astronomy? Ask an Astronomer. Web. 08 Feb.
2011.
<http://curious.astro.cornell.edu/supernovae.php>.
 "What Are Supernovae?" Index of /. Web. 08 Feb.
2011.
<http://spider.ipac.caltech.edu/staff/vandyk/supernova.
html>.