Monday, April 15, 2013

Olivia Thomas' Quiz 4/16/2013


1. What are the life stages of a high-mass star?
A high-mass star lives a short life, rapidly fusing its core hydrogen into helium via the CNO cycle. Near the end of its life, a high-mass star expands to become a supergiant as fusion proceeds furiously in its core and surrounding shells.
2. How do high-mass stars make the elements necessary for life?
They create the elements through helium capture. The core of a high-mass star eventually becomes hot enough for fusion to produce the elemts of which we and Earth are made.
3. How does a high-mass star die?
When gravity overcomes degeneracy pressure in the iron core, the core collapses into a ball of neutrons and the star explodes in a super nova.
4. How does a star's mass determine its life story?
Stars born with masses less than 8M Sun follow life stages similar to those of our Sun, while more massive stars live short but brilliant lives and die in supernova explosions.
5. How are the lives of stars with close companions different?
Stars in close binary systems can exchange mass with each other, altering their life histories.
6. When did Supernova 1987A explode?
The light reached Earth on February 23, 1987.
7. In which hemisphere was it seen?
It could be seen from the southern hemisphere.
8. Which civilization saw Supernova 1054?
The Chinese saw Supernova 1054.
9. What happened in the Crab Nebular 959 years ago?
Supernova 1054 exploded.
10. Are neutrinos produced in a supernova explosion?
Yes neutrinos are produced in a supernova explosion.

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