Sections Review
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Vocabulary
black hole | event horizon | giant molecular cloud |
helium flash | main sequence | neutron star |
planetary nebula | protostar | red giant |
shell burning | stellar nucleosynthesis | subgiant |
supergiant | supernova | T-Tauri |
white dwarf |
Formulae
- Star main sequence lifetime = [star's mass / star's luminosity] ×
1010 years.
- Star main sequence lifetime = 1010 /
(star's mass)(p - 1), where
p = 3 for stars more massive than 30 solar masses and p = 4 for
stars less massive than 10 solar masses.
- What fundamental property of stars determines their evolution?
- Why do massive stars last for a short time as main sequence
stars but low-mass stars last a long time in the main sequence stage?
- How can you detect protostars if the surrounding
gas and dust blocks visible light?
- How do T-Tauri stars get rid of the surrounding gas and
dust from which they formed?
- What is happening in the core of a main sequence star and why is
it so stable?
- What happens to a main sequence star that has stopped fusing
hydrogen in its core?
- Are all red giants or supergiants very massive stars? Why are red giants
so big and red? What is going on inside the giants?
- What is the evolution sequence for stars around the mass of our Sun? How
long is the Sun's main sequence lifetime?
- What will happen to a hot, blue star (> 10 solar masses) during its
entire lifetime?
- What will happen to a cool, red star (< 0.5 solar masses) during its
entire lifetime?
- In which stage is most of a star's mass lost?
- How is a planetary nebula formed? What is formed at the center of
the planetary nebula? Which main sequence stars will eventually form planetary
nebulae?
- What happens in a supernova explosion? Which main sequence stars
will eventually go supernova?
- How can you distinguish planetary nebulae and supernovae from each
other and from ordinary H II regions?
- About how often does a supernova occur in a typical galaxy? Why is it
better to look for supernovae in other galaxies?
- How does the concept of stellar nucleosynthesis explain where all
of the elements on the Earth came from?
- Why is iron the limit for stellar
nucleosynthesis in red giants? Where did heavier elements than iron come from?
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last updated: 25 May 2001
Is this page a copy of Strobel's
Astronomy Notes?
Author of original content:
Nick Strobel