Estimate time scale of expansion of a star

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SUMMARY

The discussion centers on estimating the time scale of expansion of a star experiencing a sudden increase in pressure, denoted as P'. The relevant equation for this estimation is tdynamical ≈ √(R³/GM), but gravity is to be ignored in this scenario. Participants suggest using dimensional analysis to approach the problem, emphasizing the need to establish an equation of motion for the outer shell of the star without incorporating gravitational forces.

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  • Understanding of stellar dynamics and pressure effects
  • Familiarity with dimensional analysis techniques
  • Knowledge of basic physics equations related to motion
  • Concept of average density in astrophysics
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  • Research dimensional analysis in the context of astrophysics
  • Study equations of motion for fluid dynamics in stars
  • Explore the effects of pressure on stellar expansion
  • Investigate alternative models for stellar dynamics without gravity
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Astronomy students, astrophysicists, and educators looking to deepen their understanding of stellar expansion dynamics and pressure effects in astrophysical contexts.

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Homework Statement


A star experiences a sudden increase in pressure to a new value P'. Taking the average density as ρ and the radius R, estimate the time scale of expansion of the star. (Ignore gravity altogether).

Homework Equations


The only thing I can see in my notes that may (or may not) be related to this is :
tdynamical ≈ √R3/GM

The Attempt at a Solution


I'm not sure how to begin, I thought perhaps I could make an equation of motion for an outer shell and equate this to some kind of pressure but I don't know how/ am quite lost.

Any help would be much appreciated thanks.
 
Physics news on Phys.org
Did you try dimensional analysis?

You cannot use G if you should ignore gravity.
 

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