Embedded Files
Time Allotment
Time Allotment
The suggested time for exploring this discussion about the topic of the formation of elements during stellar formation and evolution is 45 minutes.
Discussion
Discussion
Evolution of Stars and the Formation of Heavier Elements
Evolution of Stars and the Formation of Heavier Elements
Star formation theory states that stars are formed when a dense region of molecular cloud collapses. During this process, fragments of clouds contract and form a stellar core known as protostar. The contraction and gravitational force of the protostar result in an increase in temperature which triggers nuclear reaction within the star upon reaching 10 million Kelvin. Throughout the reaction, neutrinos and positrons are released, slowing down the reaction. Once the contraction stops and the protostar attains its gravitational equilibrium, a main sequence star will be formed.
Red Giant
Red Giant
In the core of a main sequence star, hydrogen fuses with helium through the proton-proton chain. In addition, the gravitational force of a main sequence star forces hydrogen and helium to fuse resulting to burning of the 2 primordial elements. Furthermore, at this stage, helium is converted to carbon at the core while hydrogen is converted into helium surrounding the core which denotes the formation of the red giant. On the other hand, since massive stars possess enough energy, mass, temperature, and pressure, the star will undergo a series of stages where heavier elements are fused around the shell of the core whereas carbon will be formed through helium fusion, neon will be formed through oxygen fusion, magnesium from neon fusion, silicon from magnesium fusion, and iron from silicon fusion which denotes the formation of the red giant.
White Dwarf
White Dwarf
Considering that the majority of helium surrounding the core has been converted into carbon, the rate of reaction will decrease causing the gravitational force to act squeezing the entire star. With low mass stars, considering that the amount of energy is not enough to sustain the reaction, and that the star’s fuel has been exhausted, the outer material covering the star will eventually be blown-off leaving an inert carbon core resulting to the formation of white dwarf.
The first 3 minutes of the Big Bang focused primarily on the expansion and cooling of the universe so as to the synthesis of the first three elements. On the other hand, the second cosmological event is Stellar nucleosynthesis, a process in which heavier elements such as Beryllium (4Be) and Iron (26Fe) are formed by combining protons and neutrons from the nuclei of lighter elements.
Supernova
Supernova
Moreover, under the process of stellar nucleosynthesis, heavier elements are created in different types of stars as they die or explode and the abundance of these elements changes as the stars evolve. Stable Helium reacts with Carbon to produce oxygen and gamma rays under extreme gravitational force and temperature. Oxygen as the product of the initial reaction then reacts with Helium to form Neon and gamma rays (42He + 168O -----> 20 10Ne + 00γ). The third reaction involves carbon reacting with another Carbon forming Magnesium and gamma ray (126C + 126C -----> 2412Mg + 00γ). On the other hand, Oxygen to Oxygen fusion will create Silicon, alpha particles (Helium), and gamma rays as products. (168O + 168O ----->2814Si + 42He + 00γ). The process will continue to form heavier elements from lighter ones, but not heavier than Iron with an atomic mass of 26. Lastly, a supernova happens when the core can no longer produce the needed energy to resist gravitational force, leading to its explosion and release of large amounts of energy.
Atomic Number and Synthesis of New Elements
Atomic Number and Synthesis of New Elements
Henry Moseley
Throughout history, scientist have been working on a periodic organization of elements as to their properties and to predict new elements. This is because understanding the properties of these known elements will provide them a pattern which would help them discover new elements. Henry Gwyn Jeffreys Mosely an English chemist arranged the elements in the periodic table by using atomic number as basis. This allowed him to identify and predict any element considering the number of protons which is equal to the atomic number. In addition, he emphasized that adding proton to an element increases its atomic number and that new element will be formed.
Nuclear Reaction
Nuclear Reaction
Let's learn further!
Let's learn further!
Page updated
Google Sites
Report abuse