HeBurning-2 - HELIUM BURNING! Tessa Casanova - Chad Delfino...

HELIUM BURNING!
Tessa Casanova - Chad Delfino - Felipe Alarcon
Aqueous Geochemistry
Fall 2016

OVERVIEW
•
Nucleosynthesis
•
Proton-proton fusion
•
Triple Alpha Reaction
• CNO Cycle
•
Applications

NUCLEAR FUSION

NUCLEAR FUSION
•
Nuclear fusion is the process of light
nuclei combining to form heavier nuclei.
• For elements lighter than iron, this
process liberates energy.
•
The fusion of elements heavier than iron
takes energy rather than gives energy.
•
Stars are therefore powered by the
fusion of elements lighter than iron,
particularly of hydrogen.

PROTON-PROTON FUSION

INTRODUCTION PP FUSION
• This is the nuclear fusion process which fuels
the Sun and other stars which have core
temperatures less than 15 million Kelvin.
•
A reaction cycle yields about 25 MeV of energy.
•
This fusion reaction drives the sun’s radiance.
•
Inside stars like the sun, the extreme
temperature rips atoms into their components:
protons, neutrons and electrons.

PP-FUSION SUMMARY
NEUTRINO
POSITRON
IONIZED
PR
OTONS
DEUTERIUM
DEUTERIUM
HELIUM-3
HELIUM-4
HELIUM-3

STEP 1: PROTON FUSES
•
In the proton-proton fusion reaction, first two
protons fuse.
IONIZED
PROTONS

STEP 2. DEUTERIUM FORMATION
•
Usually the pair breaks apart again
immediately, but once in a while one of the
protons is transmuted into a neutron.
•
The resulting proton-neutron pair is
deuterium, a type of hydrogen. Also, a
positron and a neutrino are emitted.
NEUTRINO
POSITRON
DEUTERIU
M

STEP 3: DEUTERIUM-PROTON
FUSION
•
Then, another proton collides
with the deuterium nucleus,
forming a helium-3 nucleus
(two protons and a neutron)
plus a gamma ray.
•
Gamma rays eventually work
their way up from the core of
the sun and out into space in
the form of sunlight.