1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Luminosity of Polaris

  1. Mar 30, 2005 #1
    Hey.. need some help in solving this problem:


    Q) The luminosity of Polaris is 10,000 times the luminosity of the sun. The surface temperature of Polaris is about 5800 kelvins. Using k=33,640,000 find how the diameter of polaris compares with the diameter of the sun. ( Equation: D= (K)(sqrt of L ) / (T)^2

    Dp/Ds = ( k(sqrt of Lp ) / (Tp)^2 ) / ( k(sqrt of Ls) / (Ts)^2 )
    = ( sqrt of 10,000Ls ) / (5800)^2 / ( sqrt of Ls ) / (Ts)^2)

    Now i'm stuck.. Not sure what this problem is leading to.. i dont know the value of Ts and hence am not gonna get an answer.. Any help is much appreciated..
     
  2. jcsd
  3. Mar 30, 2005 #2
    anyone......?
     
  4. Mar 30, 2005 #3
    [tex]d_{polaris}=\frac{k\sqrt{L}}{T^2}=\frac{33,640,000 \sqrt{10,000}}{5800 ^2}[/tex]
    [tex]d_{sun}=\frac{k\sqrt{L}}{T^2}=\frac{33,640,000 \sqrt{1}}{T^2}[/tex]

    [tex]ratio=\frac{d_{polaris}}{d_{sun}}[/tex]
     
  5. Mar 31, 2005 #4
    The answer i'm getting is 100 ( i.e. the diameter of POlaris is 100 times that of the sun ) . Is that the correct answer?

    thanks
     
    Last edited: Mar 31, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Luminosity of Polaris
  1. Luminosity of a star (Replies: 2)

  2. Luminosity of the sun (Replies: 2)

  3. Solar luminosity (Replies: 1)

Loading...