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===Our Case M Analysis=== ====Coefficient Definitions (M)==== As has been detailed in [[SSC/Virial/PolytropesEmbedded/SecondEffortAgain#ConciseFreeEnergyExpression|an accompanying discussion]], our <font color="red">'''Case M'''</font> analysis has demonstrated that the free-energy expression governing the equilibrium structure and stability of pressure-truncated polytropic configurations can also be written as, <div align="center" id="CaseMFreeEnergyExpression"> <table border="0" cellpadding="5" align="center"> <tr> <td align="right"> <math>\mathfrak{G}^*_\mathrm{SWS}</math> </td> <td align="center"> <math>=</math> </td> <td align="left"> <math> -3\mathcal{A}_{M_\ell}\biggl( \frac{n+1}{n}\biggr) \biggl( \frac{M_\mathrm{limit}}{M_\mathrm{SWS}} \biggr)^{2} \biggl(\frac{R}{R_\mathrm{SWS}}\biggr)^{-1} +~ n\mathcal{B}_{M_\ell} \cdot \biggl( \frac{M_\mathrm{limit}}{M_\mathrm{SWS}} \biggr)^{(n+1)/n} \biggl(\frac{R}{R_\mathrm{SWS}}\biggr)^{-3/n} +~ \frac{4\pi}{3} \cdot \biggl(\frac{R}{R_\mathrm{SWS}}\biggr)^{3} \, . </math> </td> </tr> </table> </div> Written in this form, the expression highlights the functional dependence on the configuration's mass while assuming that the external pressure is held fixed. Still, the expression is identical to the [[#Overview|free-energy function given above]], but viewed in this manner the appropriate coefficient and variable substitutions are: <div align="center"> <table border="1" cellpadding="10" align="center"> <tr><td align="center"> Our <font color="red">Case M</font> Analysis </td></tr> <tr><td align="center"> <table border="0" cellpadding="5" align="center"> <tr> <td align="right"> <math>a</math> </td> <td align="center"> <math>\rightarrow</math> </td> <td align="left"> <math>3\mathcal{A}_{M_\ell}\biggl( \frac{n+1}{n}\biggr) \biggl( \frac{M_\mathrm{limit}}{M_\mathrm{SWS}} \biggr)^{2} </math> </td> </tr> <tr> <td align="right"> <math>b</math> </td> <td align="center"> <math>\rightarrow</math> </td> <td align="left"> <math>n\mathcal{B}_{M_\ell} \cdot \biggl( \frac{M_\mathrm{limit}}{M_\mathrm{SWS}} \biggr)^{(n+1)/n} </math> </td> </tr> <tr> <td align="right"> <math>c</math> </td> <td align="center"> <math>\rightarrow</math> </td> <td align="left"> <math>\frac{4\pi}{3} </math> </td> </tr> <tr> <td align="right"> <math>x</math> </td> <td align="center"> <math>\rightarrow</math> </td> <td align="left"> <math>\frac{R}{R_\mathrm{SWS}}</math> </td> </tr> <tr> <td align="right"> <math>\mathfrak{G}</math> </td> <td align="center"> <math>\rightarrow</math> </td> <td align="left"> <math>\mathfrak{G}^{*}_\mathrm{SWS} \equiv \frac{\mathfrak{G}}{E_\mathrm{SWS}} </math> </td> </tr> </table> </td></tr> </table> </div> where, drawing from [http://adsabs.harvard.edu/abs/1983ApJ...268..165S Steven W. Stahler's (1983)] work — see also our [[SSC/Structure/PolytropesEmbedded#Stahler.27s_Presentation|accompanying discussion]], <div align="center"> <table border="0" cellpadding="5" align="center"> <tr> <td align="right"> <math>M_\mathrm{SWS}</math> </td> <td align="center"> <math>\equiv</math> </td> <td align="left"> <math>\biggl( \frac{n+1}{nG} \biggr)^{3/2} K_n^{2n/(n+1)} P_\mathrm{e}^{(3-n)/[2(n+1)]} \, ,</math> </td> </tr> <tr> <td align="right"> <math>R_\mathrm{SWS}</math> </td> <td align="center"> <math>\equiv</math> </td> <td align="left"> <math>\biggl( \frac{n+1}{nG} \biggr)^{1/2} K_n^{n/(n+1)} P_\mathrm{e}^{(1-n)/[2(n+1)]} \, ,</math> </td> </tr> <tr> <td align="right"> <math>E_\mathrm{SWS} \equiv \biggl( \frac{n}{n+1}\biggr)\frac{GM_\mathrm{SWS}^2}{R_\mathrm{SWS}} </math> </td> <td align="center"> <math>\equiv</math> </td> <td align="left"> <math>\biggl( \frac{n+1}{nG} \biggr)^{3/2} K^{3n/(n+1)} P_\mathrm{e}^{(5-n)/[2(n+1)]} \, ,</math> </td> </tr> </table> </div> and, in terms of the [[SSC/Virial/PolytropesEmbedded/SecondEffortAgain#Structural_Form_Factors|structural form factors]], <math>\tilde\mathfrak{f}_M</math>, <math>\tilde\mathfrak{f}_A</math>, and <math>\tilde\mathfrak{f}_W</math>, <div align="center"> <table border="0" cellpadding="5"> <tr> <td align="right"> <math>\mathcal{A}_{M_\ell}</math> </td> <td align="center"> <math>\equiv</math> </td> <td align="left"> <math> \mathcal{A} \biggl( \frac{M_\mathrm{limit}}{M_\mathrm{tot}} \biggr)^{-2} = \frac{1}{5} \cdot \frac{\tilde\mathfrak{f}_W}{\tilde\mathfrak{f}_M^2} \, ,</math> </td> </tr> <tr> <td align="right"> <math>\mathcal{B}_{M_\ell}</math> </td> <td align="center"> <math>\equiv</math> </td> <td align="left"> <math>\mathcal{B} \biggl( \frac{M_\mathrm{limit}}{M_\mathrm{tot}}\biggr)^{-(n+1)/n} = \biggl( \frac{3}{4\pi}\biggr)^{1/n} \frac{\tilde\mathfrak{f}_A}{\tilde\mathfrak{f}_M^{(n+1)/n}} \, . </math> </td> </tr> </table> </div> ====Virial Equilibrium (M)==== Plugging these coefficient assignments into the [[#Equilibrium_Configurations|above mathematical prescription of the virial theorem]] gives the mass-radius relationship for pressure-truncated, polytropic equilibrium configurations, namely, <div align="center"> <table border="0" cellpadding="5"> <tr> <td align="right"> <math>\mathcal{B}_{M_\ell} \cdot \biggl( \frac{M_\mathrm{limit}}{M_\mathrm{SWS}} \biggr)^{(n+1)/n} \biggl( \frac{R}{R_\mathrm{SWS}} \biggr)^{(n-3)/n} </math> </td> <td align="center"> <math>=</math> </td> <td align="left"> <math>\mathcal{A}_{M_\ell}\biggl( \frac{n+1}{n}\biggr) \biggl( \frac{M_\mathrm{limit}}{M_\mathrm{SWS}} \biggr)^{2} + \frac{4\pi}{3} \biggl( \frac{R}{R_\mathrm{SWS}} \biggr)^4 \, , </math> </td> </tr> </table> </div> which matches the [[SSC/Virial/PolytropesEmbedded/SecondEffortAgain#ConciseFreeEnergyExpression|statement of virial equilibrium presented in our accompanying, more detailed analysis]]. ====Stability (M)==== Similarly, according to the [[#Stability|above-derived stability criterion]], pressure-truncated polytropic configurations will only be stable if, <div align="center"> <table border="0" cellpadding="5"> <tr> <td align="right"> <math>\frac{R_\mathrm{eq}}{R_\mathrm{SWS}} </math> </td> <td align="center"> <math>></math> </td> <td align="left"> <math>\biggl[ \frac{\mathcal{A}_{M_\ell}(n-3)}{4\pi n}\biggr]^{1/4} \biggl( \frac{M_\mathrm{limit}}{M_\mathrm{SWS}} \biggr)^{1/2} \, . </math> </td> </tr> </table> </div> Or, flipped around, the criterion for stability may be written as, <div align="center"> <table border="0" cellpadding="5"> <tr> <td align="right"> <math>\frac{M_\mathrm{limit}}{M_\mathrm{SWS}} </math> </td> <td align="center"> <math><</math> </td> <td align="left"> <math> \biggl[ \frac{4\pi n}{\mathcal{A}_{M_\ell}(n-3)}\biggr]^{1/2} \biggl( \frac{R_\mathrm{eq}}{R_\mathrm{SWS}} \biggr)^2 \, . </math> </td> </tr> </table> </div> {{ SGFworkInProgress }}
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