Estimating Central pressure in Star

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SUMMARY

The discussion focuses on estimating the central pressure of stars with masses of 0.5, 1.0, and 50 solar masses, comparing these values to the central pressure of the Sun. The Hydrostatic Equilibrium equation, dP/dr = -GM(r)p(r)/R^2, is utilized for calculations, with the known mass and radius of the Sun. To estimate the radius for other stellar masses, the scaling relation R ∝ M^{(n-1)/(n+3)} is proposed, where n varies based on the nuclear energy output mechanism. The suggestion is made to assume the Sun's radius for initial calculations.

PREREQUISITES
  • Understanding of Hydrostatic Equilibrium in stellar physics
  • Familiarity with stellar mass-radius relationships
  • Knowledge of nuclear fusion processes in stars (CNO cycle and p-p chain)
  • Basic calculus for differential equations
NEXT STEPS
  • Research the application of the Hydrostatic Equilibrium equation in stellar astrophysics
  • Explore the scaling relations for stellar mass and radius in more detail
  • Study the differences between the CNO cycle and p-p chain in stellar evolution
  • Learn about the implications of central pressure on stellar stability and evolution
USEFUL FOR

Astronomy students, astrophysicists, and anyone interested in stellar structure and evolution will benefit from this discussion.

godzilla5002
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I have a question in an assignment that says "Estimate the central pressure of 0.5, 1.0, and50 solar mass stars. Compare these pressures to the central pressure of the sun"

I can estimate for the sun using the Hydrostatic equilibrium equation:

dP/dr = -GM(r)p(r)/R^2

since I know Mass of sun is 1 solar mass and I know the radius. However, when I want to calclulate the central pressure of the other solar mass stars.. I don't know the radius.. So is there a way for coming up with that? The assignment doesn't give me any more information. Should I assume the same radius as the sun?
 
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Here's my guess:

Use the scaling relation between stellar mass and radius:
R \propto M^{\frac{n-1}{n+3}}
Where n is the exponent describing how the nuclear energy output scales with the core temperature: F \propto T^n.

(n=16 for CNO-cycle hydrogen burning. n=4 approximates hydrogen burning by p-p chain.)
 
godzilla5002 said:
I have a question in an assignment that says "Estimate the central pressure of 0.5, 1.0, and50 solar mass stars. Compare these pressures to the central pressure of the sun"

I can estimate for the sun using the Hydrostatic equilibrium equation:

dP/dr = -GM(r)p(r)/R^2

since I know Mass of sun is 1 solar mass and I know the radius. However, when I want to calclulate the central pressure of the other solar mass stars.. I don't know the radius.. So is there a way for coming up with that? The assignment doesn't give me any more information. Should I assume the same radius as the sun?

maybe they just want you to use the same radius as our sun and compare the results.
 

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