Read Chapter 18
1.) (Problem adapted from textbook:) Which one of the
following is sensible:
a.) Most white dwarf stars have masses that are similar
to that of our Sun,
but a few white dwarf stars are
up to 3 times more massive than the Sun.
b.) If you want to find a pulsar, a good place to
look would be near a
supernova remnant.
c.) The interstellar matter that surrounds black holes
is gravitationally
attracted to the black holes, rapidly
falls into black holes, and makes
X-rays that we can
detect from Earth when the matter hits the black holes.
2.) There are two ways to make supernova explosions.
White dwarfs
make Type Ia explosions. Massive stars
make Type Ib and Type II
explosions.
Describe the differences in conditions between these two
ways
to make supernova explosions.
3.) What is the idea behind the Chandrasekhar limit on the mass of a
white dwarf?
4.) What 'holds up' a neutron star?
a.) neutron degeneracy pressure
b.) thermal pressure
c.) radiation pressure
d.) none of the above
5.) Why do we see pulses from pulsars?
a.) we see light released after periodic nuclear burning of material
which flowed
onto the neutron star from a companion star
b.) we see light from one of the pulsar's magnetic poles
when the pulsar's rotation
brings one of its magnetic poles into our view
c.) we see light made when the neutron star periodically contracted and
converted
gravitational potential energy into radiative energy
d.) none of the above
6.) How are novas similar to X-ray bursts?
7.) Regarding the size of a black hole:
a.) What is the physical reasoning behind the "Schwarzschild radius"
(i.e. event horizon)?
b.) What is the equation for a "Schwarzschild radius"?
c.) If we could compress the Sun so that it would fit into the
trunk of a car
(for the sake of argument, let us say that is 1 m3),
how big would its event horizon be?
d.) Would the Schwarzschild radius be inside of or outside of the
newly-squished Sun?
8.) Regarding black holes:
a.) there are theoretical explanations for black holes, but no
observational evidence
b.) there is observational evidence for black holes, but no theoretical
explanations
c.) there are both observational evidence and theoretical explanations
for black holes