Vol. 12 No. 1 (2013): Mapana Journal of Sciences
Research Articles

Emden’s Polytropes: Gas Globes In Hydrostatic Equilibrium

  • M N Anandaram
M N Anandaram
Department of Physics, Bangalore University, Bangalore 560056, India.
DOI: https://doi.org/10.12723/mjs.24.9

Published 2013-02-20

Keywords

  • Lane-Emden polytropes,
  • gas globes,
  • hydrostatic equilibrium,
  • normalized properties,
  • all-in-one graphs,
  • computer algorithm,
  • analysis
    • ...More
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Abstract

The theory of polytropes dealing with the hydrostatic equilibrium structure of gas globes had its origin in Emden’s publication, Gaskugeln a century ago (1907). This review article has been written for students of physics and astrophysics not only to understand the theory of polytropes as the simplest of stellar models but also computationally solve the Lane-Emden equation for polytropes. Anyone can easily obtain values of normalized temperature, density, pressure and mass distribution as a function of the normalized radius or mass in any polytrope model in tabular form as well as in graphical form using the program code. Explanation of the algorithm to write a code is provided (python script on request). A graphical description of how the polytropic index determines the structure of the polytrope is also given.

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