Editing SSC/Structure/BiPolytropes/51RenormaizePart2 (section)

====Moving from the Center, Outward through the Core====

<ol>
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Remembering that the "gridline" with n = 1 is at the center of the configuration, specify value of <math>(\delta r)_n</math> at n = 2.
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Determine <math>(\delta \rho)_{1.5}</math>, which is the first radial zone.
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Determine <math>(\delta P)_{1.5}</math> from the core's equation of state.
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Evaluate the pressure gradient at n = 2 by calculating <math>\tilde{M}_r/(4\pi \tilde{r}^4)</math>, appreciating that <math>\tilde{r}_2 = (r_0 + \delta r)_2</math>.
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Knowing the pressure gradient at the n = 2 gridline, and the perturbed pressure at n = 1.5, determine <math>(\delta P)_{2.5}</math>.
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Determine <math>(\delta \rho)_{2.5}</math> from the core's equation of state.
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Knowing <math>(\delta \rho)_{2.5}</math> and <math>(\delta r)_n</math> at n = 2, determine <math>(\delta r)_n</math> at n = 3.
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Evaluate the pressure gradient at n = 3 by calculating <math>\tilde{M}_r/(4\pi \tilde{r}^4)</math>, appreciating that <math>\tilde{r}_3 = (r_0 + \delta r)_3</math>.
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Knowing the pressure gradient at the n = 3 gridline, and the perturbed pressure at n = 2.5, determine <math>(\delta P)_{3.5}</math>.
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</ol>
Repeat from #6 &hellip; until we've determined <math>(\delta r)_n</math> at n = 21, that is, the perturbation at the core/envelope interface.  Also, go ahead and evaluate the perturbed pressure gradient at the interface; ultimately we need this pressure gradient (as viewed from the perspective of the core) to match the pressure gradient as viewed from then perspective of the envelope.