This silly presentation that took long to make is suppose to illustrate how shell gamma rays can deposit more energy into the envelope of a star than gamma rays originating in the core of the star.

1
This silly presentation that took long to make is
suppose to illustrate how shell gamma rays can
deposit more energy into the envelope of a star
than gamma rays originating in the core of the
star.
2
The two skyscrapers at the left represent two
stars. The floors below ground level represent
the core and the floors above ground level
represent the envelope.
3
The runners represent two gamma rays created by
fusion. The runner in the basement is a core
gamma ray, while the runner starting at the
ground floor is a shell gamma ray. They are
racing to the top.
4
The race begins
5
The basement runner has to first climb the
basement stairs to reach the ground floor.
6
In the process he loses some energy.
7
In a similar manner, core gamma rays deposit some
of their energy in the core and enter the
envelope with less energy.
8
The runner that started on the ground floor has
much more energy as he runs through the envelope
9
So the shell gamma rays, that do not have to
bounce out of the core, bring more energy into
the envelope.
10
The basement runner has lost much of his energy
and has only a small amount left to use.
11
So core gamma rays lose most of their energy
exiting the core and lower envelope and have only
a small amount to give to the outer layers of a
star.
12
The runners approach the top of the skyscraper.
13
Both are tired.
14
The runner from the ground floor lost his energy
in the envelope.
15
While the runner from the basement lost much of
his energy just in getting out of the basement.
16
So the shell gamma rays, that do not have to
bounce out of the core, bring more energy into
the envelope. In a star this excess energy
causes the envelope to swell up and transform the
star into a giant star.
17
Even as the core of a star collapses, the
envelope can swell as energy production shifts to
shell fusion. Giant stars have very tiny cores
and energy generation in shells outside the core.
Each time a new shell fusion event begins, the
star will swell again.
18
In stars less massive than 5 solar masses the
onset of shell Hydrogen fusion causes the star to
become a giant for the first time.
Hydrogen fusion in a shell begins
19
When shell Helium fusion begins around the now
all carbon core of the star, it swells for the
second time into the giant branch.
Helium fusion in a shell begins
20
In high mass stars, the evolution is so rapid
that one shell fusion follow close on the heels
of the previous shell fusion and the star moves
into the giant region and stays there until its
explosive end.