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Stellar Evolution
formation and evolution
| Question | Answer |
|---|---|
| What temperature is required to initiate nuclear fusion in a stellar core? | 10,000,000 K |
| What is the size of a typical interstellar cloud that is dense enough to fragment into star-forming regions. | 10 parsec |
| Most sstars probably formed | in clusters |
| For gravity to contract a spinning interstellar cloud, there must be sufficient | mass |
| What is the key factor that determines the temperature, density, radius, luminosity, and pace of evolution for a prestellar object? | mass |
| The most abundant substance in a molecular cloud is | H2. |
| Protostars are located on the H–R diagram | above and to the right of the main sequence. |
| A small group of atoms does not collapse into a clump because ______ quickly disperses them. | heat |
| What effect does rotation have on the process of stellar birth? | it opposed the collapse of the cloud |
| Where is an evolutionary track found? | on the H-R diagram |
| What is the physical size of a typical white dwarf star? | About the size of Earth |
| What is the characteristic pattern observed among the ages of the globular clusters associated with our Galaxy? | They all seem to have formed in the time period between 10 and 12 billion years ago. |
| A star is located on the asymptotic giant branch of the H–R diagram | after the horizontal branch |
| a planetary nebula is | an expanding shell of gas about a star. |
| Which of the following stars is most dense? | white dwarf |
| In its last stage of evolution, the Sun will become a | white dwarf |
| What type of main-sequence stars live the longest? | M- type |
| Why dont stars live forever? | They run out of nuclear fuel in their cores. |
| What is the main-sequence (hydrogen core burning) lifetime for stars like the Sun? | 10 billion yrs |
| What is the helium flash? | The rapid fusion of helium in the electron-degenerate helium core of a red giant |
| What are the differences between the processes responsible for Type I and Type II supernovae? | Type I supernovae can only occur in binary or other multiple-star systems, whereas Type II supernovae occur in isolated single high-mass stars. |
| How much energy is carried away from a supernova in the form of neutrinos compared to the energy emitted in the form of electromagnetic radiation? | About 100 times more |
| Lighter elements are fused into elements more massive than iron in | a supernova |
| The most massive element that can be formed by fusion with a release of energy is | iron |
| Which stars eventually undergo supernova explosions? | the most massive stars |
| The supernova SN 1987A was unusual because | "all of these are true" |
| A type II supernova is produced when | the collapse of a star's core causes a shockwave that blows off the surrounding envelope of the star. |
| A supernova is an event that occurs | at the end of a supergiant stage of a high-mass star |
| Why does a carbon-detonation supernova (Type I) show little or no hydrogen in its spectrum? | This supernova is the detonation of a carbon white dwarf which contains virtually no hydrogen. |
| What property of Type I supernovae makes them useful in determining distances? | Such a supernova's peak brightness is consistent and very brilliant. |
Created by:
katesmarie
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