Test 2 Review : [Class Home Page]

Review Sheet for Test 2, February 11th, 2004

Note! Because of the missed snow day, Jan 26th, we will not complete the lecture on binary stars in time for this test. I have striked out those parts below. It will not be on this test.

1) Why is there a Main Sequence? Why the correlation between T & L on the main sequence?
2) What fraction of stars are on the Main Sequence? Why? What are their luminosity class?
3) Know luminosity classes and their location on the HR Diagram. Where are the massive stars?
4) Know spectral type and luminosity class of our Sun. How does this compare to common stars?
5) Don't forget the equation L = 4(pi)R2(sigma)T4 and how it can be used.
6) The Mass-Luminosity Relationship: Why does it exist? What is the sense of it? Which stars?
7) What are the most common stars in the galaxy? How does the Sun compare to such stars?
8) Do we see evidence of stars forming? Where do stars form? How do stars form? What starts it?
9) A star begins its life the moment it begins fusion in its core. How do proto-stars create light?
10) What are T Tauri stars? Where do we find proto-stars and T Tauri's on the HR Diagram? Why?
11) How is the CNO cycle different than the p-p chain for creating Helium from Hydrogen?
12) Why is the CNO cycle not so important in the Sun? Why does it need higher Temp & Densities?
13) What is hydrostatic equilibrium? How does the star *regulate* itself with nuclear reactions?
14) Mass is most important characteristic for predicting a stars life and evolution. Why?
15) What happens to Sun-like stars when they run out of fuel? What will they first become?
16) Where do they move on the HR diagram? Why? What's happening in the core?
17) What are the final stages of a solar mass star? What's a white dwarf? Where did it come from?
18) What about high mass stars? Why can't they end as Planetary Nebula/White Dwarfs?
19) How do the cores of massive stars evolve? What do they become after leaving the M.S.?
20) What is SN1987A? Why was it so important? What had it been before it blew up?
21) White Dwarf: Size? Density? What is their eventual fate? Are they evolving? How?
22) What holds White Dwarfs 'up' against their gravity? What is the Chandrasakhar Limit?
23) Neutron Stars: Size? Density? What holds them up? How are they created?
24) How do we observe Neutron Stars? How was the first Neutron Star detected?
25) Are all Neutron stars seen as Pulsars? Why is a pulse detected? What causes it?
26) What is required to see a Pulsar? (proper line of sight, spinning fast, strong mag. field)
27) What happens to old Pulsars? Why do they stop being pulsars? Why is their energy drained?
28) What's so special about the Crab Pulsar? What is the mass limit of a Neutron Star?
29) How massive must an object be to be a Black Hole? Can low mass things be black holes? How?
30) What is the definition of a Black Hole? How is this related to the escape velocity?
31) What is the Schwarzchild Radius? Is this also the Event Horizon? What happens there?
32) What would happen if the Sun became a Black Hole? How would it effect the Earth's orbit?
33) Where is there evidence for black holes? Is it absolutely proven we've found black holes?
34) What is an Apparent Binary? Visual Binary? Spectroscopic Binary? Eclipsing Binary?
35) Why are binary stars important in astronomy? What's special about eclipsing binaries?
36) What are the two 'stars' in an X-ray Binaries? What's special about the Hulse-Taylor pulsar?

Reading from text book: pages 321 - 363, 379 -390