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The quasar that appears the brightest in our sky, 3C 273, is located at a distance of 2.4 billion lightyears. The Sun would have to be viewed from a distance of 1300 light-years to have the same apparent magnitude as 3C 273. Using the inverse square law for light, estimate the luminosity of 3C 273 in solar units.

Respuesta :

Answer:

Explanation:

Let the luminosity of the star be I and luminosity of the sun be Isun.

2.4 billion light years = 2.4 x 10⁹ light years .

brightness = luminosity / (distance)²

Given   Sun would have to be viewed from a distance of 1300 light-years to have the same apparent magnitude as 3C 273 so

For the sun

brightness = Isun / (1300 light years )²

For star

brightness = I / (2.4 x 10⁹ light years  )²

Both these brightness are same

Isun / (1300 light years )²  =  I / (2.4 x 10⁹ light years  )²

I = Isun x (2.4 x 10⁹ light years  )² / (1300 light years )²

= Isun x 3.4 x 10¹² .

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