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Calculating luminosity given accretion power

  • Thread starter natxio
  • Start date
  • #1
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Homework Statement



I have a question regarding calculating luminosity given accretion power. I have accretion power given to me as Δm/Δt= 1.5 solar masses/yr, in order to solve for luminosity are we supposed to convert the accretion power into solar masses/seconds or is it just some kind of variable where it doesn't matter. [I have to find the luminosity in Joules/sec]

Homework Equations



Luminosity= η x (Δm/Δt) x c^2


The Attempt at a Solution



My answer would be that I do have to convert because one joule= kg x m^2/ s^2 and if I have to find the Joules/sec I cannot leave the years unconverted.

(sorry if it was a dumb question, I think I answered it myself just working through explaining it to you guys)
 

Answers and Replies

  • #2
319
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Yes, to get an answer in SI units you have to convert the accretion rate into kg/s through the conversions between solar masses to kilograms, and years to seconds. Then, you can use c in m/s and the efficiency will be a dimensionless number, so you can just multiply through and your answer will be in J/s, as you observed.
 

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