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NUCLEOSYNTHESIS
OBJECTIVES
Explain stellar nucleosynthesis
Describe the different stages in the life
cycle of stars
Cite the heavy elements formed in each
stages of star cycle
WHAT I NEED TO KNOW
What are stars
made of?
What keeps
them shinning
bright?
WHAT I KNOW
 1. Which of the following is the most accepted theory
about the formation of the universe that explains why it
continues to expand?
a. BIG BANG THEORY
b. DIVINE CREATION THEORY
c. C. STEADY STATE THEORY
d. OSCILATING THEORY
WHAT I KNOW
1. Which of the following is the most accepted
theory about the formation of the universe that
explains why it continues to expand?
a.BIG BANG THEORY
b.DIVINE CREATION THEORY
c.C. STEADY STATE THEORY
d.OSCILATING THEORY
WHAT I KNOW
2. Which of the following is not considered as
light elements?
A. HELIUM
B. HYDROGEN
C. LITHIUM
D. IRON
WHAT I KNOW
2. Which of the following is not considered as
light elements?
A. HELIUM
B. HYDROGEN
C. LITHIUM
D. IRON
WHAT I KNOW
3. Which of the following is true about
nucleosysthesis?
A. It is the division of atomic particle.
B. The combination of elements to form
compound.
C. It is the creation of everything including all
the matter in the universe.
WHAT I KNOW
3. Which of the following is true about
nucleosysthesis?
A. It is the division of atomic particle.
B. The combination of elements to form
compound.
C. It is the creation of everything including all
the matter in the universe.
WHAT I KNOW
4. Which process is responsible for the formation
of light elements such as Hydrogen and helium?
A. Big Bang nucleosythesis
B. Stellar nucleosythesis
C. Supernova nucleosythesis
D. Terrestrial nucleosythesis
WHAT I KNOW
4. Which process is responsible for the formation
of light elements such as Hydrogen and helium?
A. Big Bang nucleosythesis
B. Stellar nucleosythesis
C. Supernova nucleosythesis
D. Terrestrial nucleosythesis
WHAT I KNOW
 5. Which element is the lightest and at the same time the
most abundant in outer space?
 A. Hydrogen
 B. Helium
 C. Lithium
 D. Iron
WHAT I KNOW
 5. Which element is the lightest and at the same time the
most abundant in outer space?
 A. Hydrogen
 B. Heliem
 C. Lithium
 D. Iron
WHAT`S IN
 BIG BANG –the
exponential expansion of
a singularity 13.8 billion
years ago.
 -(cosmology) the cosmic
explosion that is
hypothesized to have
marked the origin of the
universe
WHAT`S IN
WHAT`S IN
WHAT`S IN
WHAT`S IN
Right after the BIG BANG,
+
0
the p , the n and the e
were flying around
without control.
WHAT`S IN
When it started to cool down, the
quarks started making primitive
elements:
3 minutes after the Big Bang protons
and neutrons formed Hydrogen and
Helium ( Big Bang Nucleosyhthesis)
WHAT`S IN
WHAT`S IN
Hydrogen, 1 proton, 1 neutron
WHAT`S IN
Hydrogen, 1 proton, 1 neutron
WHAT`S IN
Hydrogen, 1 proton, 1 neutron
WHAT`S IN
After 200 million
years H and He
started undergoing
STELLAR
NUCLEOSYSTHESIS
Those elements
started forming
stars.
WHAT`S IN
STELLAR -stars
NUCLEOSYSTHESIS-
- formation/synthesis
of elements in the
core of the star
Star n. a self-luminous gaseous
spherical celestial body of great
mass which produces energy by
means of nuclear fusion reactions
In the stars, because of
high pressure, the
elements started bonding
and forming heavier
elements
CLASSIFYING STARS
bigger
The
or
hotter the star is,
the brighter it is.
Protostar n. an early stage in the
evolution of a star, after the beginning
of the collapse of the gas cloud from
which it
is formed, but before
sufficient contraction has occurred to
permit initiation of nuclear reactions
at its core.
MAIN SEQUENCE
STAR-Hydrogen
undergoes
nuclear fusion
and the star
becomes stable
RED GIANT
the star expands
when the hydrogen is
depleted at the core
and starts burning
Helium
-
WHITE DWARFThe remnant of
a red giant star
that has blown
off its material
into space
BLACK DWARFa hypothetical
remnant of a
white dwarf that
has cooled
down
When a super
red giant star`s
core runs out of
its
helium,
it
explodes,dispersi
ng elements into
space
PROTON-PROTON CHAIN REACTION
Hydrogen fuse with other Hydrogen nuclie
to form He
-This powers the main sequence stars
PROTON-PROTON CHAIN REACTION
CNO CYCLE
Carbon,Nitrogen,Oxygen ( CNO) cycle is
used in the stars * times bigger than the
sun to convert Hydrogen into He
CNO CYCLE
Tri-Alpha Process
In the red giant stars that has run out of
hydrogen in its core,fusion of Helium
powers the stars
Fusion of Helium produces carbon
Alpha Ladder Process
This process forms heavier elements
until Iron in the core of the red super
giant stars
It starts with Carbon fusing with
helium with every product fusing
helium until it forms Iron
Alpha Ladder Process
NEUTRON CAPTURE
Iron formed in the core of the
star captures a neutron to
form heavy elements.
Neutron capture can be
SLOW or RAPID
NEUTRON CAPTURE
S- process is the process of
forming heavier elements than
iron over long periods of time
NEUTRON CAPTURE
R-process has a faster rate of
capturing neutrons before
seed nucleus undergoes
radioactive decay