SSC/Stability/BiPolytrope00CompareApproaches - Revision history

Joel2: /* Related Discussions */

2024-07-08T22:22:24Z

Related Discussions

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	{{~~LSU_HBook_footer~~}}		{{ SGFfooter }}

Joel2: /* Radial Oscillation Frequencies */

2024-07-08T22:21:55Z

Radial Oscillation Frequencies

← Older revision		Revision as of 18:21, 8 July 2024
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	==Radial Oscillation Frequencies==		==Radial Oscillation Frequencies==

	In a [[~~User:Tohline/~~SSC/Stability/~~BiPolytrope0_0~~#Five_Mode_Summary\|separate chapter]], we have summarized some of the quantitative characteristics of five radial oscillation modes that we have determined analytically for bipolytropes that have <math>~(n_c, n_e) = (0,0)</math>. Table 1 details some of these characteristics; among them is the dimensionless oscillation frequency,		In a [[SSC/Stability/BiPolytrope00#Five_Mode_Summary\|separate chapter]], we have summarized some of the quantitative characteristics of five radial oscillation modes that we have determined analytically for bipolytropes that have <math>~(n_c, n_e) = (0,0)</math>. Table 1 details some of these characteristics; among them is the dimensionless oscillation frequency,
	<div align="center">		<div align="center">
	<math>~\sigma_c^2 \equiv \frac{3\omega^2}{2\pi \gamma_c G \rho_c} \, .</math>		<math>~\sigma_c^2 \equiv \frac{3\omega^2}{2\pi \gamma_c G \rho_c} \, .</math>
Line 296:		Line 296:
	</table>		</table>

	Our [[~~User:Tohline/~~SSC/Structure/BiPolytropes/~~Analytic0_0~~#Associated_Oscillation_Frequency\|free-energy analysis]] of these bipolytropic configurations has shown that each model's characteristic radial oscillation frequency is given by the expression,		Our [[SSC/Structure/BiPolytropes/Analytic00#Associated_Oscillation_Frequency\|free-energy analysis]] of these bipolytropic configurations has shown that each model's characteristic radial oscillation frequency is given by the expression,
	<div align="center">		<div align="center">
	<table border="0" cellpadding="5" align="center">		<table border="0" cellpadding="5" align="center">

Joel2: /* Sequences */

2024-07-08T22:20:58Z

Sequences

← Older revision		Revision as of 18:20, 8 July 2024
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	</table>		</table>
	</div>		</div>
	Figure 1 displays several such equilibrium sequences across the <math>~(q,\nu)</math> plane — see also a [[~~User:Tohline/~~SSC/Structure/BiPolytropes/~~Analytic0_0~~#Illustration\|related figure associated with our free-energy determination of stability]]. The curves show how <math>~\nu</math> varies with <math>~q</math> along sequences for which the specified density ratio is <math>~\tfrac{1}{2}</math> (blue), <math>~\tfrac{1}{4}</math> (green), and <math>~\tfrac{1}{10}</math> (maroon). We have employed a free-energy analysis (see summary, below) to examine whether a transition from stable to unstable configurations is encountered while traversing — that is, while ''evolving'' along — such sequences.		Figure 1 displays several such equilibrium sequences across the <math>~(q,\nu)</math> plane — see also a [[SSC/Structure/BiPolytropes/Analytic00#Illustration\|related figure associated with our free-energy determination of stability]]. The curves show how <math>~\nu</math> varies with <math>~q</math> along sequences for which the specified density ratio is <math>~\tfrac{1}{2}</math> (blue), <math>~\tfrac{1}{4}</math> (green), and <math>~\tfrac{1}{10}</math> (maroon). We have employed a free-energy analysis (see summary, below) to examine whether a transition from stable to unstable configurations is encountered while traversing — that is, while ''evolving'' along — such sequences.

	<table border="0" cellpadding="10" align="left"><tr><td align="center">		<table border="0" cellpadding="10" align="left"><tr><td align="center">

Joel2: /* Physical Properties */

2024-07-08T22:17:54Z

Physical Properties

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	</div>		</div>

	[[~~User:Tohline/~~SSC/Structure/BiPolytropes/~~Analytic0_0~~#gdefinition\|Our study of equilibrium configurations has shown]] that once, for example, the pair of parameters, <math>~q</math> and <math>~\rho_e/\rho_c</math>, has been specified, other properties of the associated equilibrium configuration can be succinctly expressed in terms of the function,		[[SSC/Structure/BiPolytropes/Analytic00#gdefinition\|Our study of equilibrium configurations has shown]] that once, for example, the pair of parameters, <math>~q</math> and <math>~\rho_e/\rho_c</math>, has been specified, other properties of the associated equilibrium configuration can be succinctly expressed in terms of the function,
	<div align="center">		<div align="center">
	<table border="0" cellpadding="5" align="center">		<table border="0" cellpadding="5" align="center">

Joel2: /* Comparing Stability Analyses of Zero-Zero Bipolytropes */

2024-07-08T22:17:03Z

Comparing Stability Analyses of Zero-Zero Bipolytropes

Joel2: Created page with "FORCETOC =Comparing Stability Analyses of Zero-Zero Bipolytropes= {{LSU_HBook_header}} In separate chapters we have discussed the following interrelated aspects of Bipolytropes that have $~(n_c,n_e) = (0,0)$ :

Using a [[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#BiPolytrope_with_nc_.3D_0_and_ne_.3D_0|detailed force-balance analysis to develop an analytic description of their equilibrium structure]..."

2024-07-08T22:12:31Z

Created page with "__FORCETOC__  =Comparing Stability Analyses of Zero-Zero Bipolytropes= {{LSU_HBook_header}} In separate chapters we have discussed the following interrelated aspects of Bipolytropes that have <math>~(n_c,n_e) = (0,0)</math>: <ul> <li>Using a [[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#BiPolytrope_with_nc_.3D_0_and_ne_.3D_0|detailed force-balance analysis to develop an analytic description of their equilibrium structure]..."

New page

__FORCETOC__

=Comparing Stability Analyses of Zero-Zero Bipolytropes=
{{LSU_HBook_header}}

In separate chapters we have discussed the following interrelated aspects of Bipolytropes that have <math>~(n_c,n_e) = (0,0)</math>:
<ul>
<li>Using a [[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#BiPolytrope_with_nc_.3D_0_and_ne_.3D_0|detailed force-balance analysis to develop an analytic description of their equilibrium structure]]</li>
<li>Using a [[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#Free_Energy|free-energy analysis]] to analytically identify the [[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#Equilibrium_Condition|properties of equilibrium structures]]; see also, an explicit, analytic evaluation of the statement of ''[[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#Virial_Equilibrium|Virial Equilibrium]]''</li>
<li>Developing the [[User:Tohline/SSC/Stability/BiPolytrope0_0Details#Radial_Oscillations_of_a_Zero-Zero_Bipolytrope|Linear Adiabatic Wave Equation]] (LAWE) as it applies separately to the [[User:Tohline/SSC/Stability/BiPolytrope0_0Details#Core|core]] and to the [[User:Tohline/SSC/Stability/BiPolytrope0_0Details#Envelope|envelope]] of zero-zero bipolytropic configurations</li>
<li>Identifying a [[User:Tohline/SSC/Stability/BiPolytrope0_0Details#Eureka_Regarding_Prasad.27s_1948_Paper|method to ''analytically'' solve the matching LAWEs]] for a certain subset of configurations</li>
<ul>
<li>A [[User:Tohline/SSC/Stability/BiPolytrope0_0#Radial_Oscillations_of_a_Zero-Zero_Bipolytrope|summary of this solution technique]], along with the [[User:Tohline/SSC/Stability/BiPolytrope0_0#Eigenvector|first illustrative analytic specification of an eigenvector]]</li>
<li>The derivation of [[User:Tohline/Appendix/Ramblings/Additional_Analytically_Specified_Eigenvectors_for_Zero-Zero_Bipolytropes#Searching_for_Additional_Eigenvectors_of_Zero-Zero_Bipolytropes|analytically specifiable eigenvectors having a variety of mode quantum numbers]]</li>
</ul>
<li>A [[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#Stability_Condition|free-energy analysis of the global stability]] of zero-zero bipolytropes</li>
</ul>

Building on these separate discussions, here we examine what might be learned from a comparison of the two traditional approaches to stability analysis, namely:  (1) solutions of the LAWE, and (2) a free-energy analysis.

==Key Attributes of Equilibrium Configurations==
===Physical Properties===

[[File:CommentButton02.png|right|100px|This adopted parameter notation pays tribute to the notation that was introduced by Chandrasekhar and his collaborators in the early 1940s in papers associated with the discovery of the Schönberg-Chandrasekhar mass limit.]]Aside from specifying its radius, <math>~R</math>, and total mass, <math>~M_\mathrm{tot}</math>, there are three particularly interesting ''dimensionless'' parameters that characterize the internal structure of a bipolytrope having <math>~(n_c,n_e) = (0,0)</math>. They are, the radial location of the core/envelope interface,
<div align="center">
<math>~q \equiv \frac{r_i}{R} \, ;</math>
</div>
the ratio of the density of the envelope material to the density of the core, <math>~0 \le \rho_e/\rho_c \le 1</math>; and the fraction of the total mass that is contained in the core,
<div align="center">
<math>~\nu \equiv \frac{M_\mathrm{core}}{M_\mathrm{tot}} \, .</math>
</div>
Identifying a unique bipolytropic configuration requires the specification of two of these three dimensionless parameters; the third parameter is, then, necessarily determined via what we will refer to as the,

<div align="center" id="PrimaryAlgebraicConstraint">
<font color="#770000">'''Primary Algebraic Constraint'''</font><br />
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~\frac{\rho_e}{\rho_c} </math>
</td>
<td align="center">
<math>=</math>
</td>
<td align="left">
<math>~\frac{q^3(1-\nu)}{\nu(1-q^3)} \, .</math>
</td>
</tr>
</table>
</div>
It is also relatively straightforward to appreciate that, in dimensional units, the value of the central density is,
<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~\rho_c</math>
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~\frac{3M_\mathrm{tot}}{4\pi G R^3} \cdot \frac{\nu}{q^3} \, .</math>
</td>
</tr>
</table>
</div>

[[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#gdefinition|Our study of equilibrium configurations has shown]] that once, for example, the pair of parameters, <math>~q</math> and <math>~\rho_e/\rho_c</math>, has been specified, other properties of the associated equilibrium configuration can be succinctly expressed in terms of the function,
<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~g^2</math>
</td>
<td align="center">
<math>~\equiv</math>
</td>
<td align="left">
<math>
1 + \biggl(\frac{\rho_e}{\rho_c}\biggr) \biggl[ 2 \biggl(1 - \frac{\rho_e}{\rho_c} \biggr) \biggl( 1-q \biggr) +
\frac{\rho_e}{\rho_c} \biggl(\frac{1}{q^2} - 1\biggr) \biggr] \, .
</math>
</td>
</tr>
</table>
</div>
For example, the central pressure is given by the expression,
<div align="center">
<table border="0">
<tr>
<td align="right">
<math>~P_c</math>
</td>
<td align="center">
  <math>~=</math> 
</td>
<td align="left">
<math>\biggl( \frac{3}{2^3\pi} \biggr) \frac{\nu^2 g^2}{q^4} \biggl[ \frac{GM_\mathrm{tot}^2}{R^4} \biggr] \, .</math>
</td>
</tr>
</table>
</div>

===Sequences===
<table border="0" cellpadding="10" align="right"><tr><td align="center">
<table border="1" cellpadding="8" align="center">
<tr>
<td align="center"><b>Figure 1:</b><br />Equilibrium Sequences of Constant <math>~\rho_e/\rho_c</math></td>
</tr>
<tr>
<td align="center">
[[File:ConstDensitySequences.png|300px|Constant Density Sequences]]
</td>
</tr>
</table>
</td></tr></table>
Across the two-dimensional, <math>~(q,\nu)</math> parameter space that is defined by the full range of physically viable values of <math>~q</math> and <math>~\nu</math>, namely,
<div align="center">
<math>~0 \le q \le 1 \, ,</math>      and       <math>~0 \le \nu \le 1 \, ,</math>
</div>

an equilibrium model ''sequence'' can be defined by, for example, specifying that all models along the sequence have the same density jump at the interface. Drawing on the above ''[[#PrimaryAlgebraicConstraint|primary algebraic constraint]]'', each choice of <math>~\rho_e/\rho_c</math> will generate a sequence governed by the function,
<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~\nu</math>
</td>
<td align="center">
<math>=</math>
</td>
<td align="left">
<math>~\biggl[\frac{(1-q^3)}{q^3} \biggl( \frac{\rho_e}{\rho_c} \biggr) + 1\biggr]^{-1} </math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>=</math>
</td>
<td align="left">
<math>~\frac{q^3}{q^3 + (1-q^3)(\rho_e/\rho_c)} \, .</math>
</td>
</tr>
</table>
</div>
Figure 1 displays several such equilibrium sequences across the <math>~(q,\nu)</math> plane — see also a [[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#Illustration|related figure associated with our free-energy determination of stability]]. The curves show how <math>~\nu</math> varies with <math>~q</math> along sequences for which the specified density ratio is <math>~\tfrac{1}{2}</math> (blue), <math>~\tfrac{1}{4}</math> (green), and <math>~\tfrac{1}{10}</math> (maroon). We have employed a free-energy analysis (see summary, below) to examine whether a transition from stable to unstable configurations is encountered while traversing — that is, while ''evolving'' along — such sequences.

<table border="0" cellpadding="10" align="left"><tr><td align="center">
<table border="1" cellpadding="8" align="left">
<tr>
<td align="center"><b>Figure 2:</b><br />Analytic Eigenvector Constraint</td>
</tr>
<tr>
<td align="center">
[[File:EigenvectorSequence.png|300px|Analytic Eigenvector Sequence]]
</td>
</tr>
</table>
</td></tr></table>
In a separate search for eigenvectors that simultaneously satisfy the linear adiabatic wave equation (LAWE) for the core and the LAWE for the envelope (see summary, below), we discovered that eigenvectors for some radial modes of oscillation can be specified ''fully analytically'' along a sequence of equilibrium models that is defined by what we will refer to as the,

<div align="center" id="AnalyticEigenvectorConstraint">
<font color="#770000">'''Analytic Eigenvector Constraint'''</font><br />
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~g^2</math>
</td>
<td align="center">
<math>~\equiv</math>
</td>
<td align="left">
<math>~1 + 2\biggl(\frac{\rho_e}{\rho_c}\biggr) - 3\biggl(\frac{\rho_e}{\rho_c}\biggr)^2
\, .
</math>
</td>
</tr>
</table>
</div>
When combined with the above ''[[#PrimaryAlgebraicConstraint|primary algebraic constraint]]'', this is equivalent to demanding that,
<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~\nu</math>
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~\tfrac{1}{3}(1+2q^3) \, ,</math>
</td>
</tr>
</table>
</div>
and, simultaneously,
<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~\frac{\rho_e}{\rho_c}</math>
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~\frac{2q^3}{1+2q^3} \, .</math>
</td>
</tr>
</table>
</div>

The behavior of these two functions is displayed in Figure 2; the variation of <math>~\nu</math> with <math>~q</math> is traced by the dark blue squares while the variation of <math>~\rho_e/\rho_c</math> with <math>~q</math> is marked by the small, circular black dots.

==Radial Oscillation Frequencies==

In a [[User:Tohline/SSC/Stability/BiPolytrope0_0#Five_Mode_Summary|separate chapter]], we have summarized some of the quantitative characteristics of five radial oscillation modes that we have determined analytically for bipolytropes that have <math>~(n_c, n_e) = (0,0)</math>. Table 1 details some of these characteristics; among them is the dimensionless oscillation frequency,
<div align="center">
<math>~\sigma_c^2 \equiv \frac{3\omega^2}{2\pi \gamma_c G \rho_c} \, .</math>
</div>

<table border="1" cellpadding="6" align="center">
<tr>
<td align="center" colspan="7"><b>Table 1</b></td>
</tr>
<tr>
<td align="center" colspan="2">Quantum Numbers</td>
<td align="center" rowspan="2"><math>~q</math>
<td align="center" rowspan="2"><math>~\nu</math>
<td align="center" rowspan="2"><math>~\gamma_c</math>
<td align="center" rowspan="2"><math>~\gamma_e</math>
<td align="center" rowspan="2"><math>~\sigma_c^2</math>
</tr>
<tr>
<td align="center"><math>~\ell</math></td>
<td align="center"><math>~j</math></td>
</tr>
<tr>
<td align="center">2</td>
<td align="center">1</td>
<td align="right">0.794385</td>
<td align="right"> 0.668 </td>
<td align="right">2.254</td>
<td align="right">1.194</td>
<td align="right">16.45</td>
</tr>
<tr>
<td align="center">2</td>
<td align="center">2</td>
<td align="right">0.768375</td>
<td align="right"> 0.636 </td>
<td align="right">1.046</td>
<td align="right">1.209</td>
<td align="right">34.37</td>
</tr>
<tr>
<td align="center">3</td>
<td align="center">1</td>
<td align="right">0.396061</td>
<td align="right"> 0.375 </td>
<td align="right">1.023</td>
<td align="right">1.344</td>
<td align="right">12.17</td>
</tr>
<tr>
<td align="center">3</td>
<td align="center">2</td>
<td align="right">0.594040</td>
<td align="right"> 0.473 </td>
<td align="right">1.025</td>
<td align="right">1.056</td>
<td align="right">34.20</td>
</tr>
<tr>
<td align="center">3</td>
<td align="center">3</td>
<td align="right">0.645515</td>
<td align="right"> 0.513 </td>
<td align="right">1.325</td>
<td align="right">1.840</td>
<td align="right">65.97</td>
</tr>
</table>

Our [[User:Tohline/SSC/Structure/BiPolytropes/Analytic0_0#Associated_Oscillation_Frequency|free-energy analysis]] of these bipolytropic configurations has shown that each model's characteristic radial oscillation frequency is given by the expression,
<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~\sigma_\mathfrak{G}^2 \equiv \frac{3\omega_\mathfrak{G}^2}{2\pi \gamma_c G\rho_c}</math>
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~
\frac{3q^2 \nu }{5\gamma_c}\biggl[
2( 3\gamma_e - 4) f
+ 3(\gamma_e - \gamma_c)(3 - 5 g^2) \biggr] \, ,
</math>
</td>
</tr>
</table>
</div>
where,

<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~f</math>
</td>
<td align="center">
<math>~\equiv~</math>
</td>
<td align="left">
<math>1 + \frac{5}{2} \biggl( \frac{\rho_e}{\rho_c} \biggr) \biggl(\frac{1}{q^2} - 1 \biggr)
+ \biggl( \frac{\rho_e}{\rho_c} \biggr)^2 \biggl[ \biggl(\frac{1}{q^5} - 1 \biggr) - \frac{5}{2}\biggl(\frac{1}{q^2} - 1 \biggr) \biggr] \, .</math>
</td>
</tr>
</table>
</div>

Here we will restrict our discussion to models that obey the analytic eigenvector constraint, in which case,

<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~f</math>
</td>
<td align="center">
<math>~=~</math>
</td>
<td align="left">
<math>1 + \frac{5}{2} \biggl( \frac{2q^3}{1+2q^3} \biggr) \biggl(\frac{1-q^2}{q^2} \biggr)
+ \biggl( \frac{2q^3}{1+2q^3} \biggr)^2 \biggl[ \biggl(\frac{1-q^5}{q^5} \biggr) - \frac{5}{2}\biggl(\frac{1-q^2}{q^2} \biggr) \biggr] </math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=~</math>
</td>
<td align="left">
<math>1 + 5 \biggl[ \frac{q(1-q^2)}{1+2q^3} \biggr]
+ \biggl[ \frac{2q}{(1+2q^3)^2} \biggr] \biggl[ 2 (1-q^5 ) - 5q^3 (1-q^2 ) \biggr] </math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=~</math>
</td>
<td align="left">
<math>1 + 5 \biggl[ \frac{q(1-q^2)}{1+2q^3} \biggr]
+ \biggl[ \frac{2q}{(1+2q^3)^2} \biggr] \biggl[ 2 - 5q^3 +3q^5 \biggr] </math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=~</math>
</td>
<td align="left">
<math>\frac{1}{(1+2q^3)^2} \biggl\{ (1 + 4q^3 + 4q^6) + 5 [ q(1-q^2)(1+2q^3) ]
+ 2q ( 2 - 5q^3 +3q^5 )
\biggr\}</math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=~</math>
</td>
<td align="left">
<math>\frac{1}{(1+2q^3)^2} \biggl\{ (1 + 4q^3 + 4q^6)
+ q (5 - 5q^2 + 10q^3 - 10q^5 + 4 - 10q^3 + 6q^5 )
\biggr\}</math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=~</math>
</td>
<td align="left">
<math>\frac{1}{(1+2q^3)^2} \biggl\{ (1 + 4q^3 + 4q^6)
+ (9q - 5q^3 - 4q^6 )
\biggr\}</math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=~</math>
</td>
<td align="left">
<math>\frac{1}{(1+2q^3)^2} \biggl[ 1 + 9q - q^3 \biggr] \, ,</math>
</td>
</tr>
</table>
</div>
and,
<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~(3-5g^2)</math>
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~3 - 5\biggl[1 + 2\biggl( \frac{2q^3}{1+2q^3} \biggr) - 3\biggl( \frac{2q^3}{1+2q^3} \biggr)^2 \biggr] </math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~3 - \frac{5}{(1+2q^3)^2 }\biggl[(1+2q^3)^2 + 4q^3(1+2q^3) - 12q^6 \biggr] </math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~\frac{1}{(1+2q^3)^2 }\biggl[-2(1+2q^3)^2 - 20q^3(1+2q^3) + 60q^6 \biggr] </math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~\frac{1}{(1+2q^3)^2 }\biggl[-2-8q^3 - 8q^6 -20q^3 - 40q^6 + 60q^6 \biggr] </math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~- \frac{2(1 + 14q^3 - 6q^6 ) }{(1+2q^3)^2 } \, .</math>
</td>
</tr>
</table>
</div>

Hence,
<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~\sigma_\mathfrak{G}^2</math>
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~
\frac{3q^2 \nu }{5(1+2q^3)^2}\biggl[
2\biggl( \frac{3\gamma_e}{\gamma_c} - \frac{4}{\gamma_c} \biggr) \biggl( 1 + 9q - q^3 \biggr)
-6 \biggl( \frac{\gamma_e}{\gamma_c} - 1 \biggr)\biggl( 1 + 14q^3 - 6q^6 \biggr) \biggr]
</math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~
\frac{3q^2 \nu }{5(1+2q^3)^2}\biggl[
\biggl( - \frac{8}{\gamma_c} \biggr) \biggl( 1 + 9q - q^3 \biggr)
+\biggl( \frac{6\gamma_e}{\gamma_c} \biggr) \biggl( 1 + 9q - q^3
-1 - 14q^3 + 6q^6 \biggr)
+ 6 \biggl( 1 + 14q^3 - 6q^6 \biggr)
\biggr]
</math>
</td>
</tr>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~
\frac{3q^2 \nu }{5(1+2q^3)^2}\biggl[
6 ( 1 + 14q^3 - 6q^6 ) - \frac{8}{\gamma_c} \biggl( 1 + 9q - q^3 \biggr)
+6q\biggl( \frac{\gamma_e}{\gamma_c} \biggr) \biggl( 9 - 15q^2 + 6q^5 \biggr)
\biggr]
</math>
</td>

<tr>
<td align="right">
 
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~
\frac{q^2 }{5(1+2q^3)}\biggl[
6 ( 1 + 14q^3 - 6q^6 ) - \frac{8}{\gamma_c} \biggl( 1 + 9q - q^3 \biggr)
+6q\biggl( \frac{\gamma_e}{\gamma_c} \biggr) \biggl( 9 - 15q^2 + 6q^5 \biggr)
\biggr] \, ,
</math>
</td>
</tr>
</table>
</div>
where, making this last step, we have replaced the leading factor of <math>~\nu</math> with its (above) expression in terms of <math>~q</math>.

==Analysis==

If we hold <math>~q</math> and <math>~\gamma_e</math> fixed, at what value of <math>~\gamma_c</math> does the Free-energy frequency go to zero? The answer is as follows.
<div align="center">
<table border="0" cellpadding="5" align="center">

<tr>
<td align="right">
<math>~0</math>
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~
6 ( 1 + 14q^3 - 6q^6 ) - \frac{8}{[\gamma_c]_\mathrm{crit} } \biggl( 1 + 9q - q^3 \biggr)
+6q\biggl( \frac{\gamma_e}{[\gamma_c]_\mathrm{crit} } \biggr) \biggl( 9 - 15q^2 + 6q^5 \biggr)
</math>
</td>
</tr>

<tr>
<td align="right">
<math>~\Rightarrow~~~ 6 ( 1 + 14q^3 - 6q^6 ) [\gamma_c]_\mathrm{crit} </math>
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~
8 ( 1 + 9q - q^3 ) - 6q\gamma_e ( 9 - 15q^2 + 6q^5 )
</math>
</td>
</tr>

<tr>
<td align="right">
<math>~\Rightarrow~~~ [\gamma_c]_\mathrm{crit} </math>
</td>
<td align="center">
<math>~=</math>
</td>
<td align="left">
<math>~
\frac{4 ( 1 + 9q - q^3 ) - 3q\gamma_e ( 9 - 15q^2 + 6q^5 ) }{ ( 1 + 14q^3 - 6q^6 )}
</math>
</td>
</tr>
</table>
</div>

<table border="1" cellpadding="6" align="center">
<tr>
<td align="center" colspan="9"><b>Table 2</b></td>
</tr>
<tr>
<td align="center" colspan="7">from Table 1</td>
<td align="center" colspan="2">Global Stability</td>
</tr>
<tr>
<td align="center" colspan="2">Quantum Numbers</td>
<td align="center" rowspan="2"><math>~q</math></td>
<td align="center" rowspan="2"><math>~\nu</math></td>
<td align="center" rowspan="2"><math>~\gamma_c</math></td>
<td align="center" rowspan="2"><math>~\gamma_e</math></td>
<td align="center" rowspan="2"><math>~\sigma_c^2</math></td>
<td align="center" rowspan="2">?</td>
<td align="center" rowspan="2"><math>~[\gamma_c]_\mathrm{crit}</math></td>
</tr>
<tr>
<td align="center"><math>~\ell</math></td>
<td align="center"><math>~j</math></td>
</tr>
<tr>
<td align="center">2</td>
<td align="center">1</td>
<td align="right">0.794385</td>
<td align="center">0.668</td>
<td align="right">2.254</td>
<td align="right">1.194</td>
<td align="right">16.45</td>
<td align="center"><font size="+1"><b>S</b></font></td>
<td align="right">1.358</td>
</tr>
<tr>
<td align="center">2</td>
<td align="center">2</td>
<td align="right">0.768375</td>
<td align="center">0.636</td>
<td align="right">1.046</td>
<td align="right">1.209</td>
<td align="right">34.37</td>
<td align="center"><font size="+1"><b>U</b></font></td>
<td align="right">1.361</td>
</tr>
<tr>
<td align="center">3</td>
<td align="center">1</td>
<td align="right">0.396061</td>
<td align="center">0.375</td>
<td align="right">1.023</td>
<td align="right">1.344</td>
<td align="right">12.17</td>
<td align="center"><font size="+1"><b>U</b></font></td>
<td align="right">1.318</td>
</tr>
<tr>
<td align="center">3</td>
<td align="center">2</td>
<td align="right">0.594040</td>
<td align="center">0.473</td>
<td align="right">1.025</td>
<td align="right">1.056</td>
<td align="right">34.20</td>
<td align="center"><font size="+1"><b>U</b></font></td>
<td align="right">1.520</td>
</tr>
<tr>
<td align="center">3</td>
<td align="center">3</td>
<td align="right">0.645515</td>
<td align="center">0.513</td>
<td align="right">1.325</td>
<td align="right">1.840</td>
<td align="right">65.97</td>
<td align="center"><font size="+1"><b>S</b></font></td>
<td align="right">1.075</td>
</tr>
</table>

=Related Discussions=

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	=Comparing Stability Analyses of Zero-Zero Bipolytropes=		=Comparing Stability Analyses of Zero-Zero Bipolytropes=
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	In separate chapters we have discussed the following interrelated aspects of Bipolytropes that have <math>~(n_c,n_e) = (0,0)</math>:		In separate chapters we have discussed the following interrelated aspects of Bipolytropes that have <math>(n_c,n_e) = (0,0)</math>:
	<ul>		<ul>
	<li>Using a [[~~User:Tohline/~~SSC/Structure/BiPolytropes/~~Analytic0_0~~#BiPolytrope_with_nc_.3D_0_and_ne_.3D_0\|detailed force-balance analysis to develop an analytic description of their equilibrium structure]]</li>		<li>Using a [[SSC/Structure/BiPolytropes/Analytic00#BiPolytrope_with_nc_.3D_0_and_ne_.3D_0\|detailed force-balance analysis to develop an analytic description of their equilibrium structure]]</li>
	<li>Using a [[~~User:Tohline/~~SSC/Structure/BiPolytropes/~~Analytic0_0~~#Free_Energy\|free-energy analysis]] to analytically identify the [[~~User:Tohline/~~SSC/Structure/BiPolytropes/~~Analytic0_0~~#Equilibrium_Condition\|properties of equilibrium structures]]; see also, an explicit, analytic evaluation of the statement of ''[[~~User:Tohline/~~SSC/Structure/BiPolytropes/~~Analytic0_0~~#Virial_Equilibrium\|Virial Equilibrium]]''</li>		<li>Using a [[SSC/Structure/BiPolytropes/Analytic00#Free_Energy\|free-energy analysis]] to analytically identify the [[SSC/Structure/BiPolytropes/Analytic00#Equilibrium_Condition\|properties of equilibrium structures]]; see also, an explicit, analytic evaluation of the statement of ''[[SSC/Structure/BiPolytropes/Analytic00#Virial_Equilibrium\|Virial Equilibrium]]''</li>
	<li>Developing the [[~~User:Tohline/~~SSC/Stability/~~BiPolytrope0_0Details~~#Radial_Oscillations_of_a_Zero-Zero_Bipolytrope\|Linear Adiabatic Wave Equation]] (LAWE) as it applies separately to the [[~~User:Tohline/~~SSC/Stability/~~BiPolytrope0_0Details~~#Core\|core]] and to the [[~~User:Tohline/~~SSC/Stability/~~BiPolytrope0_0Details~~#Envelope\|envelope]] of zero-zero bipolytropic configurations</li>		<li>Developing the [[SSC/Stability/BiPolytrope00Details#Radial_Oscillations_of_a_Zero-Zero_Bipolytrope\|Linear Adiabatic Wave Equation]] (LAWE) as it applies separately to the [[SSC/Stability/BiPolytrope00Details#Core\|core]] and to the [[SSC/Stability/BiPolytrope00Details#Envelope\|envelope]] of zero-zero bipolytropic configurations</li>
	<li>Identifying a [[~~User:Tohline/~~SSC/Stability/~~BiPolytrope0_0Details~~#Eureka_Regarding_Prasad.27s_1948_Paper\|method to ''analytically'' solve the matching LAWEs]] for a certain subset of configurations</li>		<li>Identifying a [[SSC/Stability/BiPolytrope00Details#Eureka_Regarding_Prasad.27s_1948_Paper\|method to ''analytically'' solve the matching LAWEs]] for a certain subset of configurations</li>
	<ul>		<ul>
	<li>A [[~~User:Tohline/~~SSC/Stability/~~BiPolytrope0_0~~#Radial_Oscillations_of_a_Zero-Zero_Bipolytrope\|summary of this solution technique]], along with the [[~~User:Tohline/~~SSC/Stability/~~BiPolytrope0_0~~#Eigenvector\|first illustrative analytic specification of an eigenvector]]</li>		<li>A [[SSC/Stability/BiPolytrope00#Radial_Oscillations_of_a_Zero-Zero_Bipolytrope\|summary of this solution technique]], along with the [[SSC/Stability/BiPolytrope00#Eigenvector\|first illustrative analytic specification of an eigenvector]]</li>
	<li>The derivation of [[~~User:Tohline/~~Appendix/Ramblings/~~Additional_Analytically_Specified_Eigenvectors_for_Zero-Zero_Bipolytropes~~#Searching_for_Additional_Eigenvectors_of_Zero-Zero_Bipolytropes\|analytically specifiable eigenvectors having a variety of mode quantum numbers]]</li>		<li>The derivation of [[Appendix/Ramblings/AdditionalAnalyticallySpecifiedEigenvectors00Bipolytropes#Searching_for_Additional_Eigenvectors_of_Zero-Zero_Bipolytropes\|analytically specifiable eigenvectors having a variety of mode quantum numbers]]</li>
	</ul>		</ul>
	<li>A [[~~User:Tohline/~~SSC/Structure/BiPolytropes/~~Analytic0_0~~#Stability_Condition\|free-energy analysis of the global stability]] of zero-zero bipolytropes</li>		<li>A [[SSC/Structure/BiPolytropes/Analytic00#Stability_Condition\|free-energy analysis of the global stability]] of zero-zero bipolytropes</li>
	</ul>		</ul>