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Supernovae and Neutron Stars

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  1. Supernovae and Neutron Stars

  2. Specific textbook sections • Evolution after the main sequence: Section 19.4 • White dwarf stars: Section 20.1 • Supernovae and neutron stars: Section 20.2

  3. Core collapse of a massive star has two consequences • Massive explosion (1044 Joules) • Production of a neutron star

  4. Formation of a neutron star from stellar core • As core collapses, matter becomes compressed • Electrons and protons forced together e+p > n + nu (neutronization) • Core of the becomes a neutron fluid • Neutronization produces a burst of neutrinos • Neutron fluid in core becomes degenerate and rigid

  5. The physics of a self-gravitating neutron blob (neutron star) • Radius versus mass relation for neutron star • Notice size of neutron star • Masses extend above Chandrasekhar limit

  6. Theoretical prediction of the existence of a neutron star • The remnant after the explosion of a massive star • An object having the mass of the Sun (or more) but in an object with the diameter of Iowa City! • An equivalent to the Chandrasekhar mass (largest possible mass of a neutron star) • Do they exist?

  7. The problem of the Crab Nebula…the remnant of the supernova of 1054 AD Even today,something is powering the Crab Nebula, causing it to shine at x-rays

  8. 1968: The Discovery of Pulsars: Rotating Neutron Stars http://www.jb.man.ac.uk/~pulsar/Education/Sounds/sounds.html

  9. Pulsar properties • Highly regular pulse properties • PSR0329+54, P=0.714519699726 sec • PSR1633+24, P=0.4905065128003 sec • What in nature could provide such a perfect clock? • Demo

  10. Pulsars as rotating neutron stars demo

  11. The Crab Nebula Pulsar http://chandra.harvard.edu/photo/2002/0052/movies.html

  12. How many pulsars (neutron stars) are there in the sky? http://www.atnf.csiro.au/research/pulsar/psrcat

  13. Neutron stars: from exotica to numerous astronomical objects

  14. A final mystery…pulsar masses are nearly all AT the Chandrasekhar Limit

  15. Periods and Period Derivatives for Pulsars