What are the letters that follow the spectral sequence OBAFGKM?
A) NP
B) YZ
C) LT
D) CD
E) UV
Answer: C
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Astronomy Chapter 6
- Where would a brown dwarf be located on an H-R diagram?
- We do not know for certain whether the general trends we observe in stellar birth masses also apply to brown dwarfs. But if they do, then which of the following would be true?
- Consider a large molecular cloud that will give birth to a cluster of stars. Which of the following would you expect to be true?
- If a star is extremely massive (well over 100 solar masses), why isn't it likely to survive for long?
- The core of a protostar that will eventually become a brown dwarf shrinks until
- The surface of a protostar radiates energy while its core
- Why does the rotation of a protostar slow down over time?
- Where does a 1-solar-mass protostar appear on an H-R diagram?
- Generally speaking, how does the surface temperature and luminosity of a protostar compare to the surface temperature and luminosity of the main-sequence star it becomes?
- Close binary star systems are thought to form when
- Angular momentum plays an important role in star formation. Which of the following characteristics of a protostellar system is probably not strongly affected by the star's angular momentum?
- According to current understanding, how did the first generation of stars differ from stars born today?
- Which process is required to allow a gravitationally-collapsing gas cloud to continue to collapse?
- Under which circumstances can you be sure that the thermal pressure within a gas cloud is increasing?
- What happens to the visible light radiated by stars located within a dusty gas cloud?
- How do we learn the chemical composition of the interstellar medium?
- About what percentage of the mass of a molecular cloud is in the form of dust?
- Which two processes can generate energy to help a star or gas cloud maintain its internal thermal pressure?
- Which of the following statements about brown dwarfs is not true?
- The vast majority of stars in a newly formed star cluster are
- What is the approximate range of masses that newborn main-sequence stars can have?
- Which star spends the longest time in the protostellar phase of life?
- Approximately what core temperature is required before hydrogen fusion can begin in a star?
- When does a protostar become a main-sequence star?
- What can we learn about a star from a life track on an H-R diagram?