Theory of the Fireball

internal energy
in that sFhere;
in the isothermal sphere of temperature T and 7 ' = 1.15
C
then (5.18) becomes
Typically, p = 5, TI = 1, Tc = 3; then u = 0.15 gm/cm sec. The expres-
sion (3.33) includes all the black body radiation. If only the radiation
actually emitted to large distances is to be included (which is reasonable
at lower temperatures, Ti < 0.8) (3.37) should be used; then u will be
2
smaller, 0.1 gm/cm sec or less.
t I 2
Before the cooling wave reacnes the isothermal sphere, Ho is smaller.
This is partly compensated by the fact that Jo > 0. An interesting inter-
mediate state is when the cooling wave has just reached the blocking
layer. Tnen, using Tb
t
J1 - Jb,
"b = 1% - H1
= 1.8 and (5.14),
Clearly this makes sense only if the subtracted term in the numerator is