Astronomy 300: Homework Assignment #8
Due: FRIDAY, April 27
Consider the energy production in the Sun via the Proton Proton
Chain. If all other factors remained the same, how would
the Sun's energy production increase if its core temperature
increased by 5%?
- The temperature of the core of the Sun (where its
nuclear fusion reactions take place) is about 15 million K.
At this temperature, the average speed of particles
is insufficient for two protons to overcome the Coulomb Barrier
and come within 1 femtometer (=10-15 m =1 fermi)
of each other. Since fusion requires the protons to
come this close (where the strong nuclear force can take over),
how does the Sun manage to generate energy?
- What is the Triple Alpha Process and why
does it require much higher temperatures
to initiate than the Proton-Proton Chain?
Does the Sun use the Triple Alpha Process?
Will it ever?
- Consider a star undergoing the Triple Alpha
Process. How would a 5% increase in core temperature affect
this star's energy production? Compared to the P-P Chain
what would you say about the temperature
sensitivity of the Triple Alpha Process?
- Carrol & Ostlie, Problem 10.13 (2 points)
- Carrol & Ostlie, Problem 10.14
- Life as we know it requires complex molecules using atoms such
as Carbon, Oxygen & Iron, which exist on a solid planet made of
Nickel, Magnesium, Aluminum, etc.
Population II were formed much earlier in the history of the universe
than Population I stars. Which Population would you
consider more likely to support planets with life, and why?
What was being measured in the Homestake Mine experiment created by
Raymond Davis? Write down the reaction that the experiment used for
detection. What problem was found?
- Intitially many scientists thought the problem lay with
Davis' experimental method, or with solar models proposed by John
Bahcall. But in the early 2000's this problem was solved. How?
Hint: The solution to this problem resulted in a
Nobel Prize for Davis.