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Stellar extinction

  1. Aug 3, 2009 #1

    Sux

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    Hi! In this problem I have to calculate the distance to a cefeide star, I know visual magnitude, [tex]m_{v}[/tex], his magnitude in B range, [tex]m_{b}[/tex] and its period, [tex]P[/tex].

    Well, if I ignore extinction, I can calculate the distance with [tex]M_{V}[/tex]:

    [tex]m_{v}=M_{V}+5log(\frac{r}{10})+A_{v}[/tex]

    Where [tex]A{v}[/tex] is visual magnitude extinction.

    As I know color index:

    [tex]m_{b}-m_{v}=M_{B}-M_{V}+E_{B-V}[/tex]

    Where: [tex]E_{B-V}[/tex] is color excess.

    And:

    [tex]\frac{A_{V}}{E_{B-V}}\approx3[/tex]


    I just need to calculate absolute magnitude in B range, [tex]M_{B}[/tex], to calculate extinction and be able to calculate the distance.

    Any ideas about how could I do it?

    I apologize for my mistakes, I am still learning English.

    Thanks.
     
  2. jcsd
  3. Aug 3, 2009 #2

    negitron

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    Science Advisor

    Your English is quite good, although I don't understand what you mean by "extinction" (it means something specific in English--it's what happened to the dinosaurs). If you define it clearly, I can probably give you the correct word.
     
  4. Aug 3, 2009 #3
    Stellar extinction has to do with the loss of light due to gas/dust in the path to the observer --atmospheric extinction due to volcanic dust, extinction due to dust around a star, for example.

    It must be corrected for to determine the intrinsic brightness of a star.

    Neil
     
  5. Aug 4, 2009 #4

    Sux

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    Yes, stellar "extinction" is the loss of flux or brightness due to interstellar dust.

    Here you have it: http://nedwww.ipac.caltech.edu/level5/Mathis/Mathis1.html" [Broken]

    Thanks for the answers.
     
    Last edited by a moderator: May 4, 2017
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