Apparent visual magnitude/brightness problem

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SUMMARY

The discussion centers on calculating the brightness of a distant star using the apparent magnitude and distance. The equation m = -2.5 log(b/b0) is identified as the key formula, where 'b' represents the brightness of the star and 'b0' is the brightness of a reference star with zero magnitude. The user initially struggles with rearranging this equation but ultimately resolves the issue independently after reflection. The conversation highlights the importance of stepping back from a problem to gain clarity.

PREREQUISITES
  • Understanding of astronomical concepts such as apparent magnitude and brightness.
  • Familiarity with logarithmic functions and their properties.
  • Basic knowledge of star classification and reference stars.
  • Experience with mathematical problem-solving techniques.
NEXT STEPS
  • Study the derivation and applications of the magnitude equation in astrophysics.
  • Explore methods for calculating absolute magnitude and its implications.
  • Research tools for measuring stellar brightness and distance, such as photometers.
  • Learn about the relationship between distance, brightness, and luminosity in stellar astronomy.
USEFUL FOR

Astronomy students, astrophysicists, and anyone interested in stellar measurements and calculations will benefit from this discussion.

toph
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Hi

I am working on a problem that requires me to calculate the brightness of a distant star. The problem i have is that the only information i have on the star is its distance and its apparent magnitude.

I think that i can solve this problem with the equation for magnitude i.e
m = -2.5 log(b/b0)

Where b = brightness of star and b0 = brightness of reference star with magnitude zero.

What i am struggling with is how to rearrange this equation to find the brightness of the distant star.
a) Can this equation be reaaranged to find the brightness required.
b) Is there another method that can help me find the required brightness with the limited information i have.
thanks for your help.
 
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Thanks for looking but i think i have solved this problem!

I had spent several hours looking at this problem and then decided to ask for your advise.
But as is often the case when you walk away from the problem and think of something else you often realize where you were going wrong.

Thanks anyway.
 

Thread 'Magnitude of buoyant force in fluids of different densities'

The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?
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