IB Physics HL Astrophysics Option D.1: Stellar Quantities – Flashcards
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State the order of planets in decreasing distance to the sun (3)
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Neptune > Uranus > Saturn > Jupiter > Mars > Earth > Venus > Mercury;
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State the order of planets in decreasing size (3)
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Jupiter > Saturn > Uranus > Neptune > Earth > Venus > Mars > Mercury;
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Define Asteroid (1)
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Small rocky body that drifts around the solar system;
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Define Meteorites (1)
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Large meteors that land on Earth;
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Explain what is meant by a comet (2)
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Mixtures of rock and ice in very elliptical orbits around the Sun; Dust tail points along path, ice path points away from the Sun;
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Define Nebulae (1)
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Interstellar clouds of dust, hydrogen, helium and other ionised gases;
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Distinguish between stellar clusters and constellations (1)
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Constellations aren't necessarily gravitationally bound;
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Explain what is meant by a parsec (1)
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Distance at which the mean radius of Earth's orbit subtends an angle of one second of arc;
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Describe what is meant by a star in hydrostatic equilibrium (2)
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A balance between the inwards pull of gravity; against the outwards push of radiation pressure;
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Explain what is meant by a binary star system (1)
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Two stars that orbiting a common barycentre of gravity;
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Explain what is meant by a visual binary system (1)
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The two stars can be distinguished using a microscope;
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Explain what is meant by a spectroscopic binary system (2)
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The two stars can be distinguished by analysis of the spectrum of emitted light from a star; Uses doppler's effect;
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Explain what is meant by a eclipsing binary system (1)
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The two stars can be distinguished by analysis of the variation in brightness of the system;
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Describe the stellar parallax method of measuring distances, including its limitations (3)
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Further objects move more, relative to near objects; Only requires AU and parallax angle to stars / d=1/p; Only works for distances <100pc as further distances measurement becomes inaccurate;
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Distinguish between luminosity and apparent brightness (2)
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Luminosity is the total power radiated by a star; Apparent brightness is the power received per unit area;
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Explain what is meant by black body radiation of stars(1)
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Stars are considered perfect emitters, so Wien's law can be applied;
