00:01
All right, so let's say we have two stars.
00:01
We got rijl and sife in the constellation orion.
00:06
And we're told rijl has an apparent magnitude, we'll call this mr of 0 .18.
00:12
And sife has an apparent magnitude.
00:14
We'll call this ms of 2 .07.
00:18
And so the first question asks, which one is brighter? so rijl would be brighter because it has a more negative apparent magnitude or a smaller apparent magnitude.
00:30
And so just for reference, the apparent magnitude of a star is like negative 2 .5 times the log of the sort of flux, a radiant flux of the star divided by some reference value.
00:42
So you can see the more negative something is, the greater the flux is, and hence the brighter it is.
00:48
And so the next part asks us how much brighter is it actually? so if we subtract the two, if we look at the difference in brightnesses between the two, that will allow us to find this.
00:59
If we do mr minus ms, this is negative 1 .89.
01:05
And so this is equal to negative 2 .5 times the logarithm of the flux of rigel divided by the flux of sif...