hw15 - Rebekah Choi Intro to Astronomy Dr. Hans Minnich 7...

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Rebekah Choi Intro to Astronomy Dr. Hans Minnich 7 December 2009 Homework #15 3. The apparent brightness of a star is how bright it appears to our eyes.Luminosity, however, is the total amount of power that a star emits into space. Astar’s apparent brightness can be determined by measuring the amount of lightwe get from stars per square meter. Luminosity can be found if the distance ismeasured. 4. Stellar parallax is the small annual shifts in a star’s apparent position. It ismeasured by comparing observations of a nearby star made six months apart.The distance can be calculated if astronomers know the precise amount of thestar’s annual shift. Once a distance is measured, the luminosity can becalculated because of the inverse square law for light. 5. Apparent magnitudes compare how bright different stars appear in our sky.Absolute magnitudes describe stellar luminosities. They’re related to apparentbrightness and luminosity in that when spoken in those contexts, it is easier tounderstand. 12. Less massive stars have longer lives because a lifetime depends onluminosity and the
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This note was uploaded on 12/10/2009 for the course ASTRO 1501 taught by Professor Minnich during the Spring '09 term at Fordham.

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hw15 - Rebekah Choi Intro to Astronomy Dr. Hans Minnich 7...

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