23.12.1: Review Questions
Review Questions
How does a white dwarf differ from a neutron star? How does each form? What keeps each from collapsing under its own weight?
2.
Describe the evolution of a star with a mass like that of the Sun, from the main-sequence phase of its evolution until it becomes a white dwarf.
3.
Describe the evolution of a massive star (say, 20 times the mass of the Sun) up to the point at which it becomes a supernova. How does the evolution of a massive star differ from that of the Sun? Why?
4.
How do the two types of supernovae discussed in this chapter differ? What kind of star gives rise to each type?
5.
A star begins its life with a mass of 5 M Sun but ends its life as a white dwarf with a mass of 0.8 M Sun . List the stages in the star’s life during which it most likely lost some of the mass it started with. How did mass loss occur in each stage?
6.
If the formation of a neutron star leads to a supernova explosion, explain why only three of the hundreds of known pulsars are found in supernova remnants.
7.
How can the Crab Nebula shine with the energy of something like 100,000 Suns when the star that formed the nebula exploded almost 1000 years ago? Who “pays the bills” for much of the radiation we see coming from the nebula?
8.
How is a nova different from a type Ia supernova? How does it differ from a type II supernova?
9.
Apart from the masses, how are binary systems with a neutron star different from binary systems with a white dwarf?
10.
What observations from SN 1987A helped confirm theories about supernovae?
11.
Describe the evolution of a white dwarf over time, in particular how the luminosity, temperature, and radius change.
12.
Describe the evolution of a pulsar over time, in particular how the rotation and pulse signal changes over time.
13.
How would a white dwarf that formed from a star that had an initial mass of 1 M Sun be different from a white dwarf that formed from a star that had an initial mass of 9 M Sun ?
14.
What do astronomers think are the causes of longer-duration gamma-ray bursts and shorter-duration gamma-ray bursts?
15.
How did astronomers finally solve the mystery of what gamma-ray bursts were? What instruments were required to find the solution?