Formation of heavier elements during star formation and evolution

Grade 12 Physical Science Week 1
This week focuses on understanding the nature and scope of Physical Science. Students will explore its two main branches—Physics and Chemistry—along with their significance in daily life

1. Give evidence for and describe the formation of heavier elements during star formation and evolution Antolyn R. De Dios

2. Today’s target L earn about the evidence for the formation of heavier elements. U nderstand the process of nuclear fusion and other phenomena that create heavier elements during star formation  Formation of heavier Elements 2

3. Introduction In this lesson, We will have a basic understanding of the process of nuclear fusion and other phenomena that create heavier elements during star formation and evolution. We should also be able to explain how the formation of heavier elements contributes to the diversity of the periodic table. 3

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6. 7 2. Beryllium-8 + Helium-4 → Carbon-12 + gamma ray 3. Carbon-12 + Helium-4 → _______________________ Can you solve the next one? Alpha Process For Massive Stars 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. Main sequence star Main sequence star

7. evidence for the formation of heavier elements

8. Concept Map 9 Nuclear Fusion in Stars (Stellar Nucleosynthesis) Supernova Explosions Evidence for the formation of heavier elements Proton-Proton Chain Reaction Carbon-Nitrogen-Oxygen Cycle Triple-Alpha Process Alpha Process Rapid Neutron Capture Process

9. 10 Nuclear Fusion in Stars: Elements up to iron can be formed through the process of nuclear fusion in the core of a star like the Sun. As stars form and evolve, the fusion process creates heavier and heavier elements. The most massive stars can produce nuclei as heavy as iron Supernova Explosions : Elements beyond iron are made by fusion in the cores of stars during supernova explosions. Supernovae are powerful enough to create heavier elements like gallium and bromine

10. Nuclear Fusion in Stars (Stellar Nucleosynthesis 9/3/20XX 11

11. Let’s do a back story. The formation of the element started million of years ago after the big explosion. A vast cloud of dust and gas started to form. This is called Nebula The big Explosion 12

12. This vast cloud of dust and gas started to collapse due to the gravity and the gravity pull this cloud together and create a Protostar. In the center where molecules is being compress together this create high pressure and temperature. When this is enough nuclear fusion occurs starting the process called stellar nucleosynthesis. The big bang Explosion 13 Formation of stars from nebula.

13. Stellar Nucleosynthesis refers to the process of creating chemical elements through nuclear fusion reactions within stars. Nuclear Fusion where lighter elements combine to form heavier elements. The intense heat and pressure in the cores of stars enable these fusion reactions to take place 14

14. 15 Newly formed stars 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.

15. Since stars is composed primarily of hydrogen the first fusion process involves hydrogen in the process known as Main Branch Proton-proton Chain 16 Main Sequence Phase Where Hydrogen atoms fuse

16. 17 Main Branch Proton-proton Chain Step 1 : Two protons (hydrogen nuclei) collide and fuse to form a deuterium nucleus (a nucleus with one proton and one neutron), releasing a positron (a positive electron) and a neutrino. Step 2 : The deuterium nucleus collides with another proton to form a helium-3 nucleus (two protons and one neutron), releasing a gamma ray Step 3 : Two helium-3 nuclei collide, and one of them captures a proton to form a helium-4 nucleus (two protons and two neutrons), while releasing two protons

17. Name some Elements

18. Main Branch Proton-Proton Chain Reaction

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20. 21 Main Branch Proton-proton Chain This nuclear fusion releases tremendous amount of light, heat and radioactive energy as Gamma ray. Helium Core Hydrogen Shell As more and more Hydrogen is burned into Helium, Helium as heavier element becomes the core and forms a Hydrogen shell this is also the time when it attain gravitational equilibrium. Main sequence stars, thus formation of the Red Giant our Sun is at this stage. Main sequence stars

21. 22 White Dwarf If 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.

22. 23 Let’s Test your knowledge What is the name of the process that creates chemical elements by nuclear fusion reactions within stars? a. Stellar nucleosynthesis c. Supernova b. Rapid neutron capture d. Fission What is the primary composition of newly formed stars before they undergo nuclear fusion? a) Hydrogen and helium c) Iron and nickel b) Carbon and oxygen d) Nitrogen and sulfur 3. _________will be formed when protostar attains its gravitational equilibrium. Main sequence star c. Supernova b. Red Giant d. White dwarf 4. What is the term for vast cloud of dust and gas. a. Star b. Proto Star c. Nebula d. Mantle 5. During the Alpha process Beryllium fused with helium will produce____ a. Argon b. Boron c. Iron d. Carbon

23. 24 6. If the majority of helium surrounding the core has been converted into carbon, What will happen to a dwarf star? It will explode b. It will become white dwarf c. It will become red giant d. It turned into diamond 7. During the formation of a _____ hydrogen will be converted into helium in the layer surrounding the core. Protostar b. Red giant c. Supernova d. White dwarf 8. What is the process called when stars use up their nuclear fuel and undergo explosions? a. Fusion c. Rapid neutron capture b. Fission d. Supernova 9. What is the most massive star capable of producing? a. Helium b. Iron c. Carbon d. Lithium 10. What is the name of the process that creates heavier elements, from iron upwards? a. Fusion b. Fission c. Rapid neutron capture d. Supernova

24. 25 Look for the meaning of the following Proto Star Nebula Stelar Nucleosynthesis Isotopes Nuclear Fusion Main Sequence Star

25. Answer Key 1. A 2. B 3. A 4. C 5. D 6. B 7. B 8. D 9. B 10.C 9/3/20XX Presentation Title 26

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27. Supernova explosion (MASSIVE STARS) 28

28. 29 2. Beryllium-8 + Helium-4 → Carbon-12 + gamma ray 3. Carbon-12 + Helium-4 → _______________________ Can you solve the next one? Alpha Process For Massive Stars 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.

29. Main Branch Proton-Proton Chain Reaction The proton-proton chain reaction is the dominant fusion process in stars with masses similar to or less than the Sun. It involves a series of nuclear reactions that convert hydrogen into helium, releasing energy that powers the star.

30. 31 Carbon Nitrogen Cycle is a set of fusion reactions that occur in stars, particularly those more massive than the Sun. It’s one of the two main processes that stars use to convert hydrogen into helium.

31. 32 Triple Alpha Process In stars with temperatures above around 100 million Kelvin, the alpha process involves the fusion of helium nuclei (which are essentially alpha particles) to form heavier elements. Triple-alpha Process : Three helium-4 nuclei (alpha particles) combine to form carbon-12.

32. 33 Massive Stars 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 Super red giant.

33. 34 Alpha Ladder Process 6 2 2 2 2 2 2 2 2 2 8 10 12 14 16 18 20 22 24 From this point the reaction is producing Isotopes that’s why Ti is 44 instead of 48 same with the rest

34. 35 Massive star Supernova For the most massive stars, a series of fusion reactions occurs as the core contracts and heats up. When the core cannot support itself against gravity, it collapses and can trigger a supernova explosion.

35. 36 Massive star Supernova These explosions generate the tremendous heat and pressure required to fuse even heavier elements, including those beyond iron, through rapid neutron capture (r-process) and slow neutron capture (s-process). This process leads to the creation of approximately half of the atomic nuclei heavier than iron, including gold, uranium, and other elements with high atomic numbers

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37. Make a timeline diagram that shows the start to end of a star making a elements in the process. Name : ______________________ Date: __________________ Grade/Sec.:___________________ Act. #: _________________

38. 9/3/20XX 39 Presentation Title Thank you