what is a white dwarf?
- a white dwarf is the most inert core of a dead star
-electron degeneracy pressures balances the inward pull of gravity
what can happen to a white dwarf in a close binary system?
-matter form its close binary companion cab fall onto the white dwarf through an accretion disk
-accretion of matter can lead to novae and white dwarf novae
what is a neutron star?
-a ball of neutrons left over form a massive star supernova and supported by neutron degeneracy pressure
How were neutron stars discovered?
-beams of radiation form a rotating neutron star sweep through space like lighthouse beams, making the appear to pulse
-observations of these pulses wee the first evidence for neutron stars
what can happen to a neutron star in a close binary system?
-the accretion disk around a neutron star gets hot enough to produce X-rays,making the system an X-ray binary
-sudden fusion events periodically occur on the surface of an accreting neutron star,producing X-rays bursts
what is a black hole?
-a black hole is a massive object whose radius is so small that the escape velocity exceeds the sped of the light
What would it be like to visit a black hole?
-you can orbit a black hole like any other object of the same mass-black holes don't suck
-near the event horizon,time slows down and tidal forces are very strong
do black holes really exist?
-some X-rays binaries contain compact objects too massive to be neutron stars-they are almost certainly black holes
Amber Reed
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