Preface from the original version of this HyperText Book (H_Book):

November 18, 1994

Much of our present, basic understanding of the structure, stability, and dynamical evolution of individual stars, short-period binary star systems, and the gaseous disks that are associated with numerous types of stellar systems (including galaxies) is derived from an examination of the behavior of a specific set of coupled, partial differential equations. These equations — most of which also are heavily utilized in studies of continuum flows in terrestrial environments — are thought to govern the underlying physics of all macroscopic "fluid" systems in astronomy. Although relatively simple in form, they prove to be very rich in nature... <more>

Pictorial Table of Contents

Pictorial Table of Contents

Context

Principal Governing Equations
- Continuity Equation
- Euler Equation
  - Rotating Reference Frame
  - Jay Call's Hybrid Scheme
- <math>1^\mathrm{st}</math> Law of Thermodynamics
- Poisson Equation

Supplemental Relations
- Total Pressure
  - Quartic Temperature Solution

Global Energy Considerations

Applications

Spherically Symmetric Configurations

Introduction (Alternate Introduction)

Structure:

Solution Strategies:

Detailed Force-Balance
(Introduction)

Virial Equilibrium
(Introduction)

Example Solutions:
Uniform-density sphere
	Isolated …	✓	✓
	Embedded in an External Medium …	✓	✓
Polytropes
	Isolated …	✓	✓
	Embedded in an External Medium …	✓	✓
Isothermal sphere
	Isolated …	✓	✓
	Embedded in an External Medium (Bonnor-Ebert Sphere) …	✓	✓
Zero-temperature White Dwarf — Overview Power-law density distribution — Overview
BiPolytropes (also referred to as Composite Polytropes)		Overview	Overview
	Core-Envelope Structure with <math>~(n_c,n_e) = (0,0)</math> …	✓	✓
	Core-Envelope Structure with <math>~(n_c,n_e) = (5,1)</math> …	✓	✓
Limiting Masses — Summary

Stability:

Solution Strategy

Virial Stability

Bipolytrope Generalization

Example Solutions:

Dynamics:

Spherical Collapse:

Free-Fall
Homologous Collapse
- Stellar Cores with n = 3 — investigation by Goldreich & Weber (1980, ApJ, 238, 991)
- Generalization to Arbitrary Polytropic Index