How can I combine star equations to find the average density of stars?

In summary, the speaker has an upcoming exam and has been practicing past exam questions. They are stuck on a couple of questions and are seeking help. They provide two equations, [1] L = M^3.3 and [2] L = R^2*T^4, and ask to combine them to show that T = R^2. They also mention a separate equation, L = T^B, and ask to derive the value of B. They note that B is approximately -0.7 but they are unsure of how to derive this. They also mention that all the stars in the problem have the same average density.
  • #1
tony_cruz
8
0
Right I've got an exam at half past 4, tomorrow on a Saturday! I've spent the past few days doing past exam questions and a lot of them I'm able to do or at least work out for myself after a bit of time. Here's a couple I'm really stuck on so some help would be really really appreciated.



Homework Statement


*all = signs are proportional not equal. I thought it'd be easier than sticking k's everywhere.

Combine equations [1] and [2] to show to a good approximation that T = R^2
Assume that all these stars have the same average density.


Homework Equations


[1] L = M^3.3
[2] L = R^2*T^4


The Attempt at a Solution


Don't really know where to start with this one. I've tried re-arranging all of the equations and substituting in, but I always get stuck very early on. Mathmatical derivations really aren't my strong point.

On a similar vain, I have this equation.


Show that L = T^B and derive the value of B
(I know B is ~-0.7 btw, I just don't know how to derive that)
again = is actually proportional
 
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  • #2
How is the mass related to volume and volume to radius?

and use "Assume that all these stars have the same average density."
 

FAQ: How can I combine star equations to find the average density of stars?

What are star equations and derivations?

Star equations and derivations refer to mathematical formulas and methods used to understand and describe the behavior of stars. This can include equations related to star formation, energy production, and evolution.

How are star equations and derivations used in scientific research?

Star equations and derivations are essential tools in astrophysics and astronomy research. They allow scientists to make predictions about the behavior of stars and test theories about their formation and evolution.

What are some common star equations and derivations?

Some common star equations and derivations include the Hertzsprung-Russell diagram, which plots a star's luminosity against its temperature, and the mass-luminosity relationship, which relates a star's mass to its luminosity.

How are star equations and derivations derived?

Star equations and derivations are derived through a combination of observational data and theoretical models. Scientists collect data on stars and use it to develop and refine equations and derivations that accurately describe their behavior.

Are star equations and derivations constantly evolving?

Yes, star equations and derivations are constantly evolving as scientists gather new data and refine their understanding of stars. As technology advances and new discoveries are made, equations and derivations may be updated or replaced to better describe the behavior of stars.

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