The Evolution of Massive Stars

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The Evolution of Massive Stars
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The Fate of 10, 20, or 30 solar mass stars
Eta Carinae possibly a 100 solar mass star what
will it do next?
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The Evolution of massive stars picks up where low
mass stellar evolution endsthe C,O core
continues to contract
In innermost core, successively hotter nuclear
reactions generate heavier nuclei as ashes
until Iron. This is the peak of the curve of
binding energy
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Following iron synthesis, core collapse occurs
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Prediction of core collapse generation of a
Neutron Star

• Process of neutronization
• ep gt n nu

A ball of neutrons the size of Iowa City with the
mass of the Sun
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The Neutron Star
This is the end product of a truly massive star
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Predicted Consequences of Massive Star Evolution

• Huge explosion 1044 Joules total energy
  radiated by the Sun in its lifetime
• Pulse of neutrinos as core collapses
• Pollution of the interstellar medium as
  explosion blows off the outer stellar core
• Birth of the neutron star

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Prediction 1 Huge explosion supernova
Simulated appearance of the supernova of 1006
ADbetween crescent moon and Venus in brightness
for a few weeks
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The most recent visible supernova SN1987A
burst of neutrinos observed at beginning of
supernova explosion
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Feature 3 Pollution of the Interstellar
Medium
Cassiopeia A expanding cloud of metal-rich
debris from a supernova in about 1680 today the
brightest radio source in the sky
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Where is Cas A?
An interstellar dark cloud in front of it
prevented a spectacle at the time of the Royal
Society
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Neutron Stars do they exist?
An object with the mass of the Sun crammed into a
ball this big
The end product of massive star evolution
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Neutron Stars a brief history

• Basic physics understood in the 1930s
• At that time, no known counterparts
• In the 1950s and 1960s, more and more strange
  objects found, but where were the neutrons stars,
  or did they even exist?
• The case of the Crab Nebula (supernova of 1054 AD)

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The Crab Nebula (M1)
Its expanding!
http//antwrp.gsfc.nasa.gov/apod/ap011217.html
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For years, the key to the Crab Nebula was there
is plain sight

• In 1968 the breakthrough came