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Stars & Stellar Evolution - Study Guide

Intro

Sun

How does the Sun hold itself up against self-gravity?
How is the Sun structured? What are its atmospheric layers?
What is the chemical composition of the Sun and how does it compare to those of the planets?
What fusion reaction is the Sun using (primarily) and where?
What was the solar neutrino "problem"?
What are sunspots and why are they relatively dark?
What drives the solar activity cycle?

Stellar Properties

How do we determine basic stellar properties such as surface temperature, chemical composition, luminosity, mass, size, and velocity?
How do we measure distances to stars?
What is a stellar parallax?
Are the brightest stars in the night sky just closer to us
or are they relatively far away & unusually luminous?
How does the Sun's luminosity compare to other stars?

Evolution

What does E=mc² mean and how is it particularly relevant to the fusion process?
Why does fusion require extremely high temperatures and densities?
What kinds of particles fuse in fusion reactions?
How do fusion reactions produce energy?
Where do fusion reactions occur in a star?
How do stars fuse hydrogen, helium, carbon, etc?
How do stars form?
Which stars are most numerous, which provide the most mass, which generate the most light?
How old is the Sun and when will it start to die?
What stellar property determines how quickly a star evolves (and dies)?
How does the temperature for helium fusion compare to that for hydrogen fusion?
Where are heavy elements like oxygen, calcium & iron made?
How do stars die? What are the three kinds of stellar corpses? What stellar property determines which way a star dies?
What happens to a star if it tries to fuse iron in its core?
What will the Sun become when it dies? What will most stars end up as?
How do the lifetimes of stars compare to the current age of the Universe?
How can a star's evolution be affected by being in a close stellar binary system?
What kinds of stars blow up in supernovae? What do these explosions leave behind?
How does the structure of a star change when it dies?
What is a planetary nebula?

H-R Diagrams

What do Hertzsprung-Russell diagrams plot? Why are they useful?
What is the physical significance of the "main sequence" of a Hertzsprung-Russell diagram?
What other stellar properties (apart from those explicitly plotted) can be deduced from Hertzsprung-Russell diagrams?
How are the mass and luminosity of main sequence stars related?
What is the relative size of a star which is cooler than the Sun but is more luminous?
What is the physical significance of the "main sequence turnoff"?

White Dwarfs

Neutron Stars

Black Holes

What are black holes? What are their basic properties?
How do black holes form?
What holds up a black hole against self-gravity?
What is the event horizon of a black hole? How is its size related to the mass of a black hole?
When a star becomes a black hole, where does the star's mass go?
How do we detect black holes?
What is the maximum mass of a black hole?
What happens to the appearance of an object as it falls into a black hole?
Can you see out of a black hole?

revised 12 Nov 2007