Theory of the Fireball

The fraction of the Planck spectm beyond u = 10 is only about Y$, so
that dssion of these frequencies is negligible.
Table VII. Ultraviolet Absorption: Spectral Regions { hv in ev) with
Large Absorption as a Function of Temperature for p = O.lpo
T I.L > 10-3 LL > m’l
2,000 4.7 - 7.2 5.5 - 7.2
3,000 3.9 . 7.2 4.7 - 7.2
4,000 3.5 - 7.2 4.6 - 7.2
6,000 4.0 - 7.1 5.8 - 6.0
8,000 2.7 - 6.3 None
12,000 All 2.7 - 3.5
The ultraviolet can, hawever, be transported quite easily at 8000~
and even more easily at 12,000° if there is a temperature gradient . Such
a gradient is always available, whether we have adiabatic conditions
(Secs. 3, 5f) or a strong cooling wave (Sec. 5d) Therefore, there will
be a flow of ultraviolet radiation at the radiating temperature, defined
in Sec. 5, which will be shown (Secs. 5d, 5f) to be about 10,OOOo or
slightly less. To calculate this flow, we should determine the tempera-
ture gradient from considerations such as Sec. 5d or 5f, and then insert
this into the radiation fluw equation. This is similar t o (5.3) except
that only the ultraviolet contribution to the flow should be taken into
account.
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