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44 Cards in this Set
- Front
- Back
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Q. What is the energy source for stars? |
A. Fusion: When hydrogen atoms combine to form Helium atom. |
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Q. What is the composition of sun? |
A. 70% hydrogen, 28% Helium, 2% heavier objects. |
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Q. How much greater is the suns mass than earth's? |
A. 333,000 times the mass of Earth |
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Q. What is it called when gravitational forces balance pressure forces? Gravitational force is due to the weight of all the layers above. |
A. Gravitational equilibrium. |
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Q. Elementary particles with a very tiny mass that usually travel close to the speed of light and pass through ordinary matter almost undisturbed. Pass directly through sun and tell us what's happening in core? |
A. Neutrinos
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Q. How hot is the sun's surface and core temperatures? |
A. Surface= 5800 K Core= 4000 K |
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Q. The sun's visible surface? (is 6000 K) |
A. Photosphere |
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Q. outermost layer of solar atmosphere - 1 million K? |
A. Corona |
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Q. unbound electrons and nuclei? |
A. Plasma
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Q. a measure of how fast atoms and molecules are moving? |
A. Temperature. |
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Q. Release energy because some of the mass of the starting nuclei is converted into energy when they join? |
A. Fusion Reactions |
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Q. a flow of charged particles from the sun? |
A. Solar Wind |
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Q. Field inhibits convection. Keeps hot gas out, allows gas already there to cool more. *are caused by intense magnetic fields that inhibit convection. |
A. Sunspots |
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Q. caused by magnetic activity. Are solar eruptions that send X-rays and charged particles into space. |
A. Solar Flares
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Q. An ejected bubble of highly energetic charged particles? |
A. Coronal Mass ejections |
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Q. Amount of energy emitted per unit time? |
A. Luminosity |
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Q. Amount of energy that reaches earth. |
A. apparent brightness |
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Q. The apparent shift in position of a nearby object against a background of more distant objects. |
A. Parallax |
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Q. What is the sun's spectral type? |
A. G2 |
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Q. Why are giants and super giants more luminous? |
A. Because they are larger |
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Q. Low density cluster, maybe fewer than 1000 stars total, contain youngish stars, found in galactic plane, stars are slowly drifting apart, produced by Milky Way |
A. Open clusters |
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Q. High density cluster, with millions of stars, contain old stars, found in galactic halo, stars are tightly bound by gravity, Milky Way no longer produces. |
A. Globular Clusters
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Q. The extinction due to dust is not equally effective at all wavelengths. The shorter the wavelength, the higher the extinction -- blue light is affected more strongly than red light. Therefore, stars behind a lot of dust look redder than they really are. |
A. Interstellar reddening |
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Q. In/near molecular clouds, have a disk & jet, are bigger and more luminous. These are all properties of…. |
A. Younger stars
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Q. Objects less massive than .08 Msun. Central temperatures never get hot enough for fusion. |
A. Brown Dwarf |
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Q. How long is the sun's life cyle? |
A. 11 billion years |
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Q. Last part of cycle for low mass main sequence star that produces pulsations and wind become violent and eject outer layers (1 million years). |
A. Planetary Nebulae. |
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Q. About how many stars are binary stars? |
A. Half. |
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Q. How much mass do white dwarfs have and how big are they? |
A. Same mass as sun and about as big as earth.
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Q. What is the maximum size for a white dwarf? |
A. 1.4 Msun |
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Q. What are the two causes/types of supernovae? |
A. massive star supernovae, white dwarf supernovae. |
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Q. Iron core of massive star can't be supported, collapses into a neutron star, outer layers expelled. |
A. Massive star supernovae. |
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Q. Begins as White Dwarf in close binary system that reaches White Dwarf limit, causing total explosion. |
A. White Dwarf Supernovae.
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Q. Are created when giant stars die in supernovas and their cores collapse, with the protons and electrons essentially melting into each other to form neutrons. |
A. Neutron Stars |
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Q. About how big are neutron stars and what are they made out of? |
A. City size with mass that is 1.4 times sun and are mostly made of iron. |
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Q. Is caused by a neutron star (which happens after super nova). Will only happen if magnetic axis is inclined relative to its rotation axis OR beamed radiation points toward us. |
A. Pulsars |
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Q. Consist of a neutron star or black hole accreting material from a star similar to our sun. |
A. X-rays binaries. |
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Q. What is the mass of neutron stars? |
A. 1.4-3Msun. |
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Q. are a result of super nova. An object whose gravity is so powerful that not even light can escape it. |
A. Black hole |
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Q. The spherical surface of a black hole where the escape velocity equals the speed of light. |
A. Event Horizon |
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Q. Objects that emit brief, powerful bursts of gamma rays. Can create the most luminous events in the universe. |
A. Gamma Ray Bursts |
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Q. Super nova of an extremely massive star (called Hypernova) AND Collision of 2 neutron stars (both likely for a BH) |
A. Favored theory is 2 mechanisms |
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Q. How long and thick is the disk of the Milky Way? |
A. 100,000 ly across and 1000 ly thick |
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Q. Sites of strong star formation: we see dust HII regions, blue stars, lots of gas. |
A. Spiral Arms |
