Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Star expansion

  1. May 12, 2009 #1
    Hi,

    When the core of a star shrinks during its evolution, does it always lead to the expansion of the star? If not, why? What cases would cause it to expand?

    Thanks in advance,
    Maria
     
  2. jcsd
  3. May 13, 2009 #2
    No, sometimes gravity from the mass of the star overcomes the energy from core fusion to shrink the star into a white dwarf about the volume of the Earth (which is held up by electron degeneracy) or a neutron star about the diameter of a city (which is held up by neutron degeneracy) or it collapses to a black hole.

    http://imagine.gsfc.nasa.gov/docs/science/know_l2/dwarfs.html
    http://imagine.gsfc.nasa.gov/docs/science/know_l1/neutron_stars.html
    http://imagine.gsfc.nasa.gov/docs/science/know_l2/black_holes.html

    One case that causes it to expand is when the core fuses helium into carbon.

    http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971016.html

    Arthur Eddington used the Hertzsprung-Russell diagram to demonstrate stellar physics.
    http://en.wikipedia.org/wiki/Hertzsprung-Russell_diagram
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Star expansion
  1. No star (Replies: 1)

  2. Star expansion? (Replies: 2)

  3. Strange Stars (Replies: 6)

Loading...