Friday, July 29, 2011
The Neutron Star When a star runs out of fuel it eventually goes through a gravitational collapse. There are several possible outcomes, and three come about by simply taking into account only the mass of the star that has just collapsed. If the star is less than 1.5 solar masses, then a white dwarf is formed. Yet if its mass is larger than 5 solar masses, it will create a black hole. What about if the star’s mass was in between those two points? Well, that’s when a neutron star is formed. Due to the inward collapse of such a star, electrons combine with protons to form neutrons – thus giving the resultant celestial body the name “neutron star”. Neutron stars characteristically have extremely high densities. Anything falling into a neutron star is super-accelerated by gravity (which is 100 billion times stronger than what we experience on earth). “If you dropped a marshmallow onto a neutron star, it would have the energy of an atomic bomb,” says Chip Meegan from the Marshal Space Flight Center of NASA. Neutron stars also have insanely strong magnetic fields, approximately 2 x 1011 times those of Earth. These stars are usually very hot. The degeneracy pressure due to the Pauli exclusion principle (no two neutrons or any other fermions can occupy the same place and quantum state simultaneously) ensures the neutron star’s stability and prevents it from collapse. (The only situation in which a neutron star would collapse into a black hole is if it is gradually absorbing matter from an accompanying binary star.) Pulsars! Very simply, pulsars are rotating neutron stars. Because they conserve the angular momentum of the stars from which they were formed, pulsars can spin at rates over 700 times revolutions per second. They stream jets of highly energetic particles (which have speeds close to that of light) out from their magnetic poles, producing extremely powerful beams of radiation. This combined with their rotational movement allows them to appear as if they are pulsing when they are observed. The rotational and magnetic axes of these stars are misaligned, which causes the beam of light from the jets to “sweep” around as the pulsar rotates, giving rise to the lighthouse effect.

The Neutron Star

When a star runs out of fuel it eventually goes through a gravitational collapse. There are several possible outcomes, and three come about by simply taking into account only the mass of the star that has just collapsed. If the star is less than 1.5 solar masses, then a white dwarf is formed. Yet if its mass is larger than 5 solar masses, it will create a black hole. What about if the star’s mass was in between those two points? Well, that’s when a neutron star is formed. Due to the inward collapse of such a star, electrons combine with protons to form neutrons – thus giving the resultant celestial body the name “neutron star”.

Neutron stars characteristically have extremely high densities. Anything falling into a neutron star is super-accelerated by gravity (which is 100 billion times stronger than what we experience on earth). “If you dropped a marshmallow onto a neutron star, it would have the energy of an atomic bomb,” says Chip Meegan from the Marshal Space Flight Center of NASA. Neutron stars also have insanely strong magnetic fields, approximately 2 x 1011 times those of Earth. These stars are usually very hot. The degeneracy pressure due to the Pauli exclusion principle (no two neutrons or any other fermions can occupy the same place and quantum state simultaneously) ensures the neutron star’s stability and prevents it from collapse. (The only situation in which a neutron star would collapse into a black hole is if it is gradually absorbing matter from an accompanying binary star.)

Pulsars!

Very simply, pulsars are rotating neutron stars. Because they conserve the angular momentum of the stars from which they were formed, pulsars can spin at rates over 700 times revolutions per second. They stream jets of highly energetic particles (which have speeds close to that of light) out from their magnetic poles, producing extremely powerful beams of radiation. This combined with their rotational movement allows them to appear as if they are pulsing when they are observed. The rotational and magnetic axes of these stars are misaligned, which causes the beam of light from the jets to “sweep” around as the pulsar rotates, giving rise to the lighthouse effect.

Posted at 6:55 PM 56 notes Tags: astronomy astrophysics gravitational collapse neutron stars physics pulsars science astrophysics sayitwithscience education information knowledge facts star stars universe galaxy space white dwarf pulsar black hole

Notes

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  11. gondragon reblogged this from ohmysagan and added:
    Good explanation :3
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  22. astronomicalconsiderations reblogged this from the-life-quixotic and added:
    Neutron stars are so fucking cool.
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