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  This is a mosaic image, one of the largest ever taken by
  NASA's Hubble Space Telescope of the Crab Nebula, a
  six-light-year-wide expanding remnant of a star's
  supernova explosion. Japanese and Chinese astronomers
  recorded this violent event nearly 1,000 years ago in
  1054, as did, almost certainly, Native Americans. The
  orange filaments are the tattered remains of the star and
  consist mostly of hydrogen. The rapidly spinning neutron
  star embedded in the center of the nebula is the dynamo
  powering the nebula's eerie interior bluish glow. The blue
  light comes from electrons 

Chandra, Hubble, and Spitzer image NGC 1952

  A star's spectacular death in the constellation Taurus was
  observed on Earth as the supernova of 1054 A.D. Now,
  almost a thousand years later, a super dense object --
  called a neutron star-- left behind by the explosion is
  seen spewing out a blizzard of high-energy particles into
  the expanding debris field known as the Crab Nebula. X-ray
  data from Chandra provide significant clues to the
  workings of this mighty cosmic "generator," which is
  producing energy at the rate of 100,000 suns. This
  composite image uses data from three of NASA's Great
  Observatories. The Chandra X-ray image is shown in blue,
  the Hubble Space Telescope optical image is in red and
  yellow, and the Spitzer Space Telescope's infrared image
  is in purple. 

  The X-ray image is smaller than the others because
  extremely energetic electrons emitting X-rays radiate away
  their energy more quickly than the lower-energy electrons
  emitting optical and infrared light. Along with many other
  telescopes, Chandra has repeatedly observed the Crab
  Nebula over the course of the mission's lifetime. The Crab
  Nebula is one of the most studied objects in the sky,
  truly making it a cosmic icon.

Solar Nucleosynthesis -- proton-proton chain


  pp   p + p --> H2 + e+ + v_e 100 q < 0.420 MeV
  pep  p + e- + p --> H2 + v_e 0.4 q = 1.442 MeV
  hep  He3 + p --> He4 + v_e 0.00002 q < 18.773 MeV
  Be7  Be7 + e- --> Li7 + v_e 15 q = 0.862 MeV 89.7%, q = 0.384 MeV 10.3%
  B8   B8 --> Be7 + e+ + v_e 0.02 q < 15 MeV

Relevant papers by John N. Bahcall, Sarbani Basu, M. H. Pinsonneault:

Wikipedia | Main sequence

Wikipedia | Stellar evolution


  There are four (4) fates for the end of stars depending on
  their masses and the masses of their cores: 

  Brown Dwarfs--less than 0.6 Ms (Main Sequence .076-0.8 Ms)

  Stars less than about 0.6 solar masses, when nuclear fuel
  is used up, gravitational collapse shrinks the star, but
  no more than the gas temperature-pressure-volume laws of
  classical physics allow. We have not found any white dwarf
  less massive than 0.6 solar masses. Part of the answer is
  that the universe may not be old enough for lower mass
  stars to have evolved off the main sequence. 

  White Dwarfs--0.08 and 1.44 Ms (Main Sequence 0.8-8 Ms)

  Stars with core masses between 0.08 and 1.44 solar masses
  are destined to become white dwarfs. White dwarfs are
  degenerate matter. Further collapse is halted by electron
  degeneracy pressure. See pages 456-459 in your textbook.
  The vast majority of stars are in this mass range and are
  destined to become white dwarfs

  Neutron Stars--1.44 and 2.9 Ms (Main Sequence 8-30 Ms) 

  Core masses between 1.44 and 2.9 solar masses overcome
  electron degeneracy pressure and collapse to form neutron
  stars, a star that is essentially one gigantic nucleus.
  Further collapse is halted by neutron degeneracy

  Black Holes--3 or more Ms (Main Sequence > 30 Ms)

  But for cores with mass of 3 or more solar masses, neutron
  degeneracy pressure does not stop the collapse and the
  star becomes a black hole with zero physical size, but
  with all the mass. Gravity really wins! 

  In each case, gravity eventually wins, but, to what extent
  is determined by the mass and the relative pressures of
  the quantum mechanical forces, electron and neutron
  degeneracy pressure.

Hubblecast | The Death of Stars (6 min)

Astronomy Picture of the Day Archive