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Binary star system

  1. Dec 14, 2009 #1
    Please could you let me know how to find out apparent magnitude of a star when you know the apparent magnitude of the binary star system?
    p.s. the distance between the observer and the system is'nt given.

    I have the luminosities of both the stars as well as absolute magnitudes of both the stars.
  2. jcsd
  3. Dec 15, 2009 #2
    Apparent magnitude of a star at a distance d depends on the flux F (of light) from the star through a unit area at that distance d. In other words, F=L/(4 pi d^2). Note that d appears in the equation. But it cancels if the distance of the two stars is the same (as in a binary) when computing the relative magnitudes.

    Here's the formula for changing between fluxes and apparent magnitudes:
    Last edited: Dec 15, 2009
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