Question: Which of the following main sequence stars would be the most massive?
Answer Choices:
M2 F6 K2 O9
Answer:
O9
Question: If a cluster shows a main sequence turnoff point at G2, what is the approximate age of the cluster?
Answer Choices:
200 million years old 10 million years old 4-5 billion years old 10 billion years old
Answer:
4-5 billion years old
Question: The difference between a red giant and a red supergiant is…
Answer Choices:
red giants were massive main sequence stars. red supergiants were massive main sequence stars. red supergiants were cooler main sequence stars. red giants were mostly type O and B stars while red supergiants were K and M stars.
Answer:
red supergiants were massive main sequence stars.
Question: What core temperature is required for helium fusion to occur?
Answer Choices:
100 million K 1 million K 15 million K 100 billion K
Answer:
100 million K
Question: The red giant stage occurs when…
Answer Choices:
the star is finished burning helium in its core the star stops hydrogen shell burning and reverts back to core fusion hydrogen shell burning begins causing the star to expand, become more luminous, and have a cooler surface temperature the star starts burning helium in its core
Answer:
hydrogen shell burning begins causing the star to expand, become more luminous, and have a cooler surface temperature
Question: Which of the following would be most likely to show a main sequence turnoff point around F9?
Answer Choices:
OB Stellar Association Spheroid Cluster Young Open Cluster Globular Cluster
Answer:
Globular Cluster
Question: Which of the following stages is best explained as the outer layers of a star blown into space and illuminated by a hot central star?
Answer Choices:
red supergiant helium flash planetary nebula red giant
Answer:
planetary nebula
Question: A star is no longer considered a main sequence star when…
Answer Choices:
another star comes along it starts fusing helium in its core a younger star comes along a more massive star comes along it stops fusing hydrogen in its core
Answer:
it stops fusing hydrogen in its core
Question: Which of the following main sequence stars is most likely to undergo a helium flash later in its evolution?
Answer Choices:
O1 G9 K6 B3
Answer:
G9
Question: Why do older stars have lower heavy-element abundances?
Answer Choices:
The relative abundances of heavy elements was much higher in the past, but today young stars use up lots of hydrogen in their masses. The interstellar medium from which they formed was not enriched with heavy elements formed in stellar interiors. Only stars with low heavy-element abundances are easily observed. This is a survivorship bias. Old stars are lower mass and are not able to fuse elements beyond carbon.
Answer:
The interstellar medium from which they formed was not enriched with heavy elements formed in stellar interiors.
Question: Which of the following main sequence stars would be the most massive?
Answer Choices:
M2 F6 K2 O9
Answer:
O9
Question: How do elements such as oxygen and sulfur form?
Answer Choices:
In the interior of Sun-sized stars. In the interior of high-mass stars. In the interior of planetary/nebulae. By nuclear fusion reactions of H2 main sequence stars after the red giant stage. Through the process of stellar nucleosynthesis.
Answer:
In the interior of high-mass stars. Through the process of stellar nucleosynthesis.
Question: Compared to the Sun a Red Giant star is…
Answer Choices:
brighter in apparent magnitude higher in luminosity larger in radius more dense higher in surface temperature
Answer:
higher in luminosity larger in radius
Question: For a Sun-sized star…
Answer Choices:
core fusion will stop when a carbon core is formed core fusion will stop when an iron core is formed core fusion will stop when a helium core is formed all core fusion will cease after the main sequence stage
Answer:
core fusion will stop when a carbon core is formed