Astronomy & Space Science · AST-311
Hydrostatic Equilibrium: Foundations
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Overview
Core model: Hydrostatic Equilibrium
A stable star exists because inward gravity is balanced locally by outward pressure gradients. This condition, hydrostatic equilibrium, does not mean the forces vanish everywhere; it means each layer has enough pressure support to carry the weight of the material above it without undergoing rapid collapse or expansion.
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Source library for this chapter
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- 01The Sun: A Nuclear Powerhouse — SummaryOpen source ↗
OpenStax Astronomy 2e
View claim-by-claim traceability3 verified claims
If gravity momentarily exceeds pressure support, the layer contracts, which usually increases density and temperature and raises pressure.
supported · checked Sep 22, 2026Stellar models that solve hydrostatic balance together with energy generation and transport reproduce measured masses, radii, luminosities, oscillation frequencies, and evolutionary tracks.
supported · checked Sep 22, 2026A stable star exists because inward gravity is balanced locally by outward pressure gradients.
supported · checked Sep 22, 2026