THE ORIGIN OF ELEMENTS

• BIG BANG NUCLEOSYNTHESIS • The is a process believed to have taken place in the early moments of the universe, shortly after the initial expansion took place according to the Big Bang theory • discover by George Gamow and Ralph Alpher 1939 .
• • Nuclear fusion - The is a process believed to have taken place in the early moments of the universe, shortly after the initial expansion took place according to the Big Bang theory. • it takes 17 minutes.
• II. STELLAR NUCLEOSYNTHESIS : This is the process by which elements are created within stars by combining the protons and neutrons together from the nuclei of lighter element
• II. HISTORY 1. Arthur Eddington – Nuclear fusion 2. George Gamow – (Gamow factor) probability of such reaction. 3. Hans Bethe – proton proton cycle / carbon nitrogen oxygen cycle
• Explosive or Supernova Nucleosynthesis : The process that takes place during the explosion of a star. Elements such as Si and Ni are formed through fast fusion.
• Cosmic Ray Spallation - The impact of fast protons or cosmic rays against the interstellar medium results in the spallation phenomenon. During this process, the heavier nuclei of carbon or oxygen fragment into lighter elements such as Be, B, and Li, making these elements more abundant compared to the ratios that result by other types of nucleosynthesis.
• Hydrogen Burning: This first stage begins with the proton- proton cycle, otherwise known as the proton-proton chain (see diagram at left), where hydrogen is converted to helium.
• C. REACTION CYCLES DURING THE SYNTHESIS OF HEAVY ELEMENTS IN STARS

  A) HYDROGEN BURNING

  B) PROTON PROTON

  C) CHAIN

  D) COULOMB REPULSION

  
• OTHER FORM OF HYDROGEN FUSION 1.1

  A) Beryllium 7

  
• another proton proton proccess

  A) boron 8

  B) boron

  
• high energy hydrogen fusion

  A) carbon nitrogen oxygen cycle

  
• Helium Burning: The second stage begins after most of the hydrogen is burned, which is around this time a main sequence star (which our Sun belongs to) turns into a Red Giant.
• Burning of Heavier Elements: If the star is massive enough, another set of nuclear fusion reactions begins. These include the burning of carbon, neon, oxygen and silicon that lead to the formation of heavier elements and finally iron
• Production of Heavier Elements than Iron: After the production of iron, the star collapses under its own gravity due to a lack of fusion, because Iron absorbs energy rather than release it. Thus, the star bursts into a supernova, where it can either turn into a neutron star or a black hole
• LIFE CYCLE OF A AVERAGE STAR

  A) STELLAR NEBULA

  B) AVERAGE STAR

  C) RED GIANT

  D) PLANETARY NEBULA

  E) WHITE DWARF

  
• LIFE CYCLE OF A MASSIVE STAR

  A) STELLAR NEBULA

  B) MASSIVE STAR

  C) RED SUPER GIANT

  D) SUPERNOVA

  E) BLACK HOLE

  F) NEUTRON STAR

  
• PROTOSTAR AND THEIR LIVES

  A) PROTOSTAR a

  
• protostar and their lives

  A) protostar b

  
• protostar and their lives

  A) protostar y

  
• ELEMENTFORMATIONIN HIGH DENSITYSTARS

  A) advance hydrogen chain

  B) beryllium

  C) helium

  D) nuclei

  
• ELEMENTFORMATIONIN HIGH DENSITYSTARS

  A) basic hydrogen chain

  B) beryllium

  C) lithium

  D) helium