Explorations: An Introduction to Astronomy (Arny), 7th Edition

Chapter 15: Stellar Remnants: White Dwarfs, Neutron Stars, and Black Holes

Thought Questions

Your Results:

1			Some astronomers have suggested that cooled white dwarfs are made of diamond. Why might it be impractical to mine them?
2			Is a white dwarf significantly different from the core of a low-mass main-sequence star? Thinking about how the speed of stellar evolution relates to the mass of the stars, and about what happens when novas occur, can you explain how you might have a binary system with an 8-solar-mass blue main-sequence star and a 1-solar-mass white dwarf?
3			Is it surprising that a pulsar is not seen in every supernova remnant? Why?
4			The period of a star is equal to its circumference divided by its rotational velocity. If a star collapses to 1/X of its previous radius, how many times shorter is the period?
5			Explain how neutron star "pulses" are different from the "pulsing" of variable stars. Are neutron stars variable stars?
6			White dwarfs, neutron stars, and black holes can be found in binary star systems with normal or giant companion stars. What happens in each of these systems?
7			A 1-solar-mass black hole would be smaller than a 1-solar-mass neutron star, which in turn would be smaller than a 1-solar-mass white dwarf. If the Sun were replaced by each of these objects, what would be the impact on the Earth's orbit? Compare the conditions close to the surface or event horizon of these objects.
8			How would you explain to an 8-year-old child that black holes may exist?
9			Suppose you jumped into a black hole feet first. What would happen to you as your feet approached its Schwarzschild radius? Hint: Think about tides on the Earth created by the Moon.
10			What would be different if you were orbiting a 16-solar-mass black hole or a 16-solar-mass star at a distance of 5 AU?

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