Sections Review
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Vocabulary
accretion disk | degenerate gas | electron degeneracy pressure |
event horizon | General Relativity | gravitational lens |
gravitational redshift | lighthouse model | neutron degeneracy pressure |
nova | pulsar | Schwarzschild radius |
Formulae
- Escape velocity = Sqrt[2G ×
Mass)/(distance to the center)], where G is the gravitational
constant.
- Event horizon (Schwarzschild radius) = 2G ×
(black hole mass)/c2, where G is the gravitational
constant, and c is the speed of light.
- Event horizon = [3 × black hole mass] kilometers, where the black
hole mass is measured in solar masses.
- Maximum size of an object = fluctuation time interval ×
speed of light.
- What type of star will become a white dwarf? Describe the
characteristics of a white dwarf.
- How does electron degeneracy pressure keep the
white dwarf from collapsing any further?
- What is the upper bound for the mass of a white dwarf? How would the fact
that stars up to 5 solar masses become white dwarfs show that stars lose mass
to the interstellar medium as they evolve? How is most of this mass lost?
- How is a neutron star created? What type of star will become a
neutron star? Describe the characteristics of a neutron star.
- How does neutron degeneracy pressure keep the
neutron star from collapsing to a point at the center?
- What is the upper bound for the mass of a neutron star?
- What are the ingredients for a pulsar?
- Why does a pulsar spin so fast?
- Why could a collapsed star spinning many times each second not be a
regular star or white dwarf?
- What type of star will become a black hole? Does anything keep it
from collapsing to a point at the center? Describe the characteristics of a
black hole.
- What is the sole determining thing that specifies the size of the
event horizon?
- What are the signatures of a black hole---observations indicating
the presence of a super-compact nearly invisible object?
- How do the rapid fluctuations of the X-rays from a black hole's
accretion disk show that the object at the center is small? If the
fluctuations were slower (taking longer to brighten and then fade), would
the implied size be smaller or larger?
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last updated: 25 May 2001
Is this page a copy of Strobel's
Astronomy Notes?
Author of original content:
Nick Strobel