ASTR 1040 UVU Hintz Test 3 – Flashcards
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T/F Apparent magnitude is a value assigned to a star based on how bright it looks in our night sky.
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True
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Absolute magnitude is defined at the magnitude all the stars would have if they were at the same distance. What is that distance?
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10 parsecs
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Mimosa and Spica are both bright stars in the sky, but Mimosa is visually brighter. Match the appropriate apparent magnitude value with the star name. Spica: Mimosa:
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Spica: .103 Mimosa: .081
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Sirus has M=1.46 and m=-1.43 Betelgeus has M=-5.01 and m=.157 What statements can you make based on provided information?
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Sirus looks brighter in the sky. Betelgeuse is the actual brighter (more luminous) star Sirus is closer than 10 parsecs Betelgeues is further than 10 parsecs
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What is the closest star to our own solar system (beyond the sun)?
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Proxima Centauri
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What is the brightest star in the night sky?
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Sirius
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Stars come in a variety of brightness's as seen from the Earth. Why is this the case?
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Stars come in a variety of brightness as seen from the earth. There is an apparent and an absolute brightness. The apparent brightness is how bright the star appears on earth. It is effected by how bright the star actually is AND its distance to earth. The absolute brightness of the star is how bright it actually is.
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T/F: Parallax, the measurement that gets distance to stars, is available for only those stars that are relative close by in our galaxy.
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True
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How does the gas and dust just hanging around in space affect what we see?
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It can make stars look fainter It scatters the blue light making stars look redder than they are. It can create spectral lines in the light from the star from elements not in the star.
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New stars are formed:
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in huge, cool dust and gas clouds.
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Of the three nebulas, which is the one that produces the stars (is the stuff the stars are made out of)?
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Dark Nebula
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What force causes the stars to form in the first place?
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Gravity
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As the gas in a nebula compresses, what happens to the temperature of the cloud?
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It increases
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How does the mass of the forming star affect the time it takes to reach hydrostatic equilibrium?
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...
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How do we know stars are forming inside the clouds?
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...
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What is the deciding factor that makes a star a main sequence star?
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Hydrogen Fusion in the core produces Hydrostatic equilibrium.
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All stars on the main sequence...
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are doing hydrogen fusion in their cores.
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What happens to the overall size of a star when it leaves the main sequence?
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It increases
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When a star leaves the main sequence, what element dominates the core?
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Helium
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Which physical property of the star determines the length of time it will stay on the main sequence?
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Mass
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Which step of evolution is the sun currently in?
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Main Sequence
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When a star is in the Horizontal Branch stage of its evolution (or life) it is
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both hydrogen shell fusion and helium core fusion.
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T/F: As the star becomes a Red Giant Star, it does have energy generation in the form of hydrogen fusion in a shell surrounding the core of the star.
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True
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Of the stages of stellar evolution we have discussed so far, which lasts for the longest period of time?
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Main Sequence
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What can we say about an AGB star?
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Hydrogen shell fusion Helium Shell Fusion Core of Carbon-Oxygen Outerlayers of Hydrogen
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A star with initial mass of less than 4 solar masses will eject its outer layers that will become a
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Planetary Nebula
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What is the appx size of a white dwarf?
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Earth Size
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What will be the final state of our sun?
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White Dwarf
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How would you classify the supernova in brightness?
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Very Bright
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What stage of a star lasts the longest?
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Main Sequence
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What is in the core of the star just at the end of all the fusion processes of a Supergiant (massive) star?
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Iron
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How did our universe get a full periodic table from just Hydrogen and Helium?
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Fusion
