.. _comp-ptrope:

********************
Composite Polytropes
********************

Composite polytropes are an extension of standard :wiki:`polytrope <Polytrope>`
models for stellar structure, to allow for discontinuities in the
density :math:`\rho` and/or the polytropic index :math:`n`.  This
appendix lays out the mathematical formalism\ [#formalism]_
underpinning them; it is intended to complement the :ref:`build-poly`
appendix, which describes how composite polytrope models can be built
using the :program:`build_poly` executable.

.. toctree::
  :maxdepth: 2

  comp-ptrope/equation-of-state.rst
  comp-ptrope/struct-equations.rst
  comp-ptrope/solution-method.rst
  comp-ptrope/physical-vars.rst
  comp-ptrope/struct-coeffs.rst

.. rubric:: Footnotes

.. [#formalism] The formalism here is based on `Mixed polytrope with density
		discontinuities` (Christensen-Dalsgaard, 2015, unpublished),
		with extensions to allow for constant-density regions.