Homework 14 Due Monday, April 5, 2004

  1. Stars A and B are equally bright as seen from Earth, but A is 60 pc away while B is 10 pc away. Which star has the greater luminosity? How many times greater is it?

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  2. Suppose two stars have the same apparent brightness, but one star is 15 x farther away than the other. What is the ratio of their luminosities? Which one is more luminous, the closer star or the farther star?

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  3. The bright star Rigel in the constellation Orion has a surface temperature about 1.6 times that of the Sun. Its luminoisity is about 64000 x the luminoisity of the sun. What is Rigel's radius compared to the radius of the Sun?

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  4. Castor is an A1 V star with an apparent brightness of 4.4 x 10-12 that of the Sun. Determine the approximate distance from the Earth to Castor (in parsecs).