At the end of their lives, all stars become either a white dwarf, neutron star, or a black hole. These are collectively known as compact objects. Since there are no longer any nuclear reactions occuring in them, they aren't really stars any more. Note that since it isn't possible to predict how much mass a star will loose during its life -- thus, you can't predict with any certainty which of these objects a given star will become.
White dwarfs all have masses less than <1> solar masses, which is known as Chandresekhar's Limit. They are balls of carbon and oxygen nuclei with free electrons that are about the size of <2>. Further graviational collapse is prevented by <3>. A white dwarf is slowly cooling down and resembles the embers of a fire. When mass from a binary companion is transferred to a white dwarf pushing its mass over Chandresekhar's Limit, a <4> occurs.
More massive stars must become neutron stars which are about the size of a <5>. These objects resemble a giant atomic nucleus held together by gravity and supported by neutron pressure. Beams of radiation are emitted from the magnetic poles of these objects. When a beam points toward us we see the neutron star as a <6>.
Black Holes are stellar remnants that have zero size -- a singularity! Gravity is so strong in their vicinity that even light cannot escape. The surface surrounding them from which light cannot escape is known as the <7> and its size is given by the Schwarzchild Radius. Since black holes cannot be seen, it is difficult to prove their existence. Their presence is most often inferred by detecting X-rays produced by their <8>.
@ qu.1.1.blank.1=1.44,2.00,0.08,3.00@ qu.1.1.blank.2=the Earth, a city,Jupiter,a singularity@ qu.1.1.blank.3=electron pressure,neutron pressure,antimatter,centripetal force@ qu.1.1.blank.4=Type I supernova,Type II supernova,nova,Type III supernova@ qu.1.1.blank.5=a city,the Earth,Jupiter,a singularity@ qu.1.1.blank.6=pulsar,black hole,gamma-ray burster,white dwarf,nova@ qu.1.1.blank.7=event horizon,photon sphere,singularity,general relativity curve@ qu.1.1.blank.8=accretion disks,formation,orbiting companions,photon spheres@ qu.1.1.grader.1=menu@ qu.1.1.grader.2=menu@ qu.1.1.grader.3=menu@ qu.1.1.grader.4=menu@ qu.1.1.grader.5=menu@ qu.1.1.grader.6=menu@ qu.1.1.grader.7=menu@ qu.1.1.grader.8=menu@ qu.1.2.mode=Blanks@ qu.1.2.editing=useHTML@ qu.1.2.name=Compact Objects@ qu.1.2.question=At the end of their lives, all stars become either a white dwarf, neutron star, or a black hole. These are collectively known as compact objects. Since there are no longer any nuclear reactions occuring in them, they aren't really stars any more. Note that since it isn't possible to predict how much mass a star will loose during its life -- thus, you can't predict with any certainty which of these objects a given star will become.
White dwarfs all have masses less than <1> solar masses, which is known as Chandresekhar's Limit. They are balls of carbon and oxygen nuclei with free electrons that are about the size of <2>. Further graviational collapse is prevented by <3>. A white dwarf is slowly cooling down and resembles the embers of a fire. When mass from a binary companion slowly builds up on the surface of a white dwarf, a <4> is likely to occur.
More massive stars must become neutron stars which are about the size of a <5>. These objects are known for their high density and extremely strong magnetic fields. Beams of radiation are emitted from the magnetic poles of these objects. The <6> model explains that we see a pulsar when one of these beams crosses are line of sight.
Black Holes are stellar remnants that have zero size -- a singularity! Gravity is so strong in their vicinity that even light cannot escape. The surface surrounding them from which light cannot escape is known as the event horizon and its size is given by the <7>. Since black holes cannot be seen, it is difficult to prove their existence. Their presence is most often inferred by detecting X-rays produced by their <8>.
@ qu.1.2.blank.1=1.44,2.00,0.08,3.00@ qu.1.2.blank.2=the Earth, a city,Jupiter,a singularity@ qu.1.2.blank.3=electron pressure,neutron pressure,antimatter,centripetal force@ qu.1.2.blank.4=nova,Type I supernova,Type II supernova,Type III supernova@ qu.1.2.blank.5=a city,the Earth,Jupiter,a singularity@ qu.1.2.blank.6=lighthouse,event horizon,angular momentum,rotational pole@ qu.1.2.blank.7=Schwarzchild radius,photon sphere,singularity,general relativity curve@ qu.1.2.blank.8=accretion disks,formation,orbiting companions,photon spheres@ qu.1.2.grader.1=menu@ qu.1.2.grader.2=menu@ qu.1.2.grader.3=menu@ qu.1.2.grader.4=menu@ qu.1.2.grader.5=menu@ qu.1.2.grader.6=menu@ qu.1.2.grader.7=menu@ qu.1.2.grader.8=menu@