释义 |
Lane-Emden Differential EquationA second-order Ordinary Differential Equation arising in the study of stellar interiors. It is given by
 | (1) |
 | (2) |
It has the Boundary Conditions
Solutions for , 1, 2, 3, and 4 are shown above. The cases , 1, and 5 can be solved analytically(Chandrasekhar 1967, p. 91); the others must be obtained numerically.
For ( ), the Lane-Emden Differential Equation is
 | (5) |
(Chandrasekhar 1967, pp. 91-92). Directly solving gives
 | (6) |
 | (7) |
 | (8) |
 | (9) |
 | (10) |
 | (11) |
The Boundary Condition then gives and , so
 | (12) |
and is Parabolic.
For ( ), the differential equation becomes
 | (13) |
 | (14) |
which is the Spherical Bessel Differential Equation
 | (15) |
with and , so the solution is
 | (16) |
Applying the Boundary Condition gives
 | (17) |
where is a Spherical Bessel Function of the First Kind (Chandrasekhar 1967, pp. 92).
For , make Emden's transformation
which reduces the Lane-Emden equation to
 | (20) |
(Chandrasekhar 1967, p. 90). After further manipulation (not reproduced here), the equation becomes
 | (21) |
and then, finally,
 | (22) |
References
Chandrasekhar, S. An Introduction to the Study of Stellar Structure. New York: Dover, pp. 84-182, 1967.
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