1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Absolute Visual Magnitude of Stars

  1. Oct 1, 2015 #1
    1. The problem statement, all variables and given/known data
    The Sun has an absolute visual magnitude of about 4.8 and a particular star has an absolute visual magnitude of –0.29. How many times more luminous is this star than the Sun, assuming these stars have similar spectral types and hence colours?

    a) 100 times
    b) 125 times
    c) 150 times
    d) 175 times
    e) 200 times

    2. Relevant equations
    Luminosity of Star 1/ Luminosity of Star 2 = (100^1/5)^M2-M1
    Where M1 and M2 are the abolute magnitudes

    3. The attempt at a solution

    = 109 times more luminous

    I am just wondering whether I have calculated correctly, given my answer is closest to a) but nearly crossing over to b)
  2. jcsd
  3. Oct 1, 2015 #2


    User Avatar

    Staff: Mentor

    Your calculations appear to be okay to me (although you've used 4.81 rather than the given 4.8 for the Sun's absolute magnitude, a minor quibble that doesn't significantly impact your query).
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted