Help Solve Supernova Assignment | Astro Community

[Froddo]

Hello Astro community, I really need help with few assignments!

First one would be about Supernova:
In a distant galaxy a supernova flash occured. When supernova reached luminosity maximum, galaxy apparent magnitude
was 17,6. Before the supernova flash the galaxy apparent magnitude was 18,0. What was the supernova's apparent magnitude at it's luminosity maximum?

Could you help me solve this and explain it to me ?

Karma !

 

[Mordred]

I believe this is the calculation your looking for

http://en.m.wikipedia.org/wiki/Mass–luminosity_relation

 

[Froddo]

I'm sorry I did a mistake in the text, there's not luminosity mentioned.

In a distant galaxy a supernova flash occured. When supernova reached brightness maximum, galaxy apparent magnitude
was 17,6. Before the supernova flash the galaxy apparent magnitude was 18,0. What was the supernova's apparent magnitude at it's brightness maximum? What I'm trying to say is that there's no luminosity mentioned, only apparent magnitude. So I'm not sure if the luminosity and mass relation would help in this case.

In short : When the supernova flashed the galaxy had 17.6 apparent magnitude, before the flash it was 18. And I need to find apparent magnitude of the supernova when flash occurred ( supernova reached max)

L.K.

 

[Borek]

Discussion continues here: https://www.physicsforums.com/showthread.php?t=674694

 

[pmacias]

Hi there! I would be happy to help you with your assignment on supernovas. To solve this problem, we can use the formula that relates apparent magnitude (m), absolute magnitude (M), and distance (d):

m = M + 5log(d/10)

In this case, we know that the galaxy's apparent magnitude before the supernova was 18.0 and after the supernova reached its maximum luminosity, it was 17.6. We also know that the distance to the galaxy remains constant, so we can set the two equations equal to each other and solve for the absolute magnitude at maximum luminosity:

18.0 = M + 5log(d/10)
17.6 = M + 5log(d/10)

Subtracting the second equation from the first, we get:

0.4 = 0

This means that the absolute magnitude at maximum luminosity must be 0.4. We can then use this value to find the apparent magnitude at maximum luminosity by rearranging the formula:

m = M + 5log(d/10)
m = 0.4 + 5log(d/10)

Since we know the distance to the galaxy remains constant, we can substitute in the values for d and solve for m:

m = 0.4 + 5log(d/10)
m = 0.4 + 5log(1)
m = 0.4

Therefore, the supernova's apparent magnitude at its luminosity maximum would be 0.4. This means that the supernova would appear much brighter in the sky than the galaxy itself, as it has a lower apparent magnitude. I hope this explanation helps! Good luck with your assignment.