Formation of Heavy Elements PDF

Quarter 3 – Module 1: “Formation of Heavy Elements” LESSON OBJECTIVES: D esc ribe the formation of heavier elements during star formation and evolution; Explain stellar nucleosynthesis; and Describe the different stages of life cycle of stars. Activity: Let’s Arrange! Arrange th...

Quarter 3 – Module 1: “Formation of Heavy Elements” LESSON OBJECTIVES: D esc ribe the formation of heavier elements during star formation and evolution; Explain stellar nucleosynthesis; and Describe the different stages of life cycle of stars. Activity: Let’s Arrange! Arrange the jumbled words into their proper order to identify the word/term. The site of element formation via fusion SRAT STAR Activity: Let’s Arrange! Arrange the jumbled words into their proper order to identify the word/term. Explosions that create and scatter heavy elements. OENUSPARV SUPERNOVA Activity: Let’s Arrange! Arrange the jumbled words into their proper order to identify the word/term. A component of atom without charge, crucial in forming heavy elements via neutron capture TONNUER NEUTRON Activity: Let’s Arrange! Arrange the jumbled words into their proper order to identify the word/term. One of the first elements formed during stellar fusion. IHUEML HELIUM Activity: Let’s Arrange! Arrange the jumbled words into their proper order to identify the word/term. The heaviest element formed during normal stellar fusion. RION IRON Activity: Let’s Arrange! Star - Stars are sites of element formation via fusion. Supernova - Explosions that create and scatter heavy elements. Neutron – A component of atom without charge, crucial in forming heavy elements via neutron capture. Helium - One of the first elements formed during stellar fusion. Iron - The heaviest element formed during normal stellar fusion.  How do elements form? Big Bang Nucleosynthesis – Formation of light elements, primarily gases. Stellar Nucleosynthesis - Formation of elements up to iron (⁵⁶Fe) in the periodic table. Supernova Nucleosynthesis - Formation of elements heavier than iron (e.g., gold, uranium). Neutron Star Mergers - Formation of the heaviest elements (e.g., platinum, uranium). 1. What are the primary composition of stars? Stars are primarily composed of hydrogen, making up about 74% of their mass. He liu m is t h e se c on d most ab u n d an t element in stars, constituting around 24% of their mass. Heavy elements, such as metals comprised the remaining 2%. 1. What is the primary composition of stars? About 4.6 billion years ago, the Sun formed from a giant molecular cloud primarily composed of hydrogen and helium, along with trace amounts of heavier elements (metals). Gravity caused the cloud to collapse, concentrating hydrogen and helium at the center. This process ignited nuclear fusion, marking the birth of the Sun as a star.  2. H o w d o s t a r s p r o d u c e e n e r g y, considering their composition? The energy in stars is produced through a process called nuclear fusion. Let’s have a review of what does an atom look like? Let’s have a review of what does an atom look like? Proton Neutron Electron Electron Orbits Let’s have a review of what does an atom look like? The atom is visualized as a nucleus surrounded by a " cloud" of electrons. The cloud represents areas where an electron is most likely to be found (probability distribution).  Nuclear Fusion r eactions power the Sun and other stars. Two light nuclei merge to form a single heavier nucleus. How do nuclear fusion occur? 1.Conditions Required for Fusion H i g h Te m p e ra t u r e : To o v e r c o m e t h e electrostatic repulsion (Coulomb barrier) between positively charged nuclei, temperatures of millions of degrees Celsius are required. At such temperatures, matter exists as plasma, a state where electrons are stripped from nuclei. High Pressure: Suf fic ient pressure ensures that nuclei are packed closely together, increasing the likelihood of collisions. How do nuclear fusion occur? 2. Plasma Formation At extremely high temperatures, gases are ionized into a plasma state, where nuclei and electrons move independently. How do nuclear fusion occur? 3. Overcoming Electrostatic Repulsion Nuclei, being positively charged, repel each other. For fusion to occur, the nuclei must collide with enough energy to overcome this repulsive force. Quantum tunneling, a phenomenon where particles pass through energy barriers, also facilitates fusion under extreme conditions.  3. How are elements heavier than hydrogen and helium created in the universe? Elements heavier than hydrogen and helium are primarily formed through nucleosynthesis processes in stars. Nucleo-: Derived from the Latin word nucleus, meaning "kernel" or "core." In this context, it refers to the nucleus of an atom. -synthesis: From the Greek word synthesis, meaning "putting together" or "combination.“  Nucleosynthesis - This is def ined as the production or creation of new elements through the process of nuclear reactions. Nucleosynthesis - This is def in ed as the production or creation of new elements through the process of nuclear reactions.  After the universe cooled slightly, the neutrons fused with protons to make nuclei of deuterium, an isotope of hydrogen. Deuterium nuclei then combined to make helium. Further reactions between protons, neutrons, and different isotopes of helium produced lithium. The hydrogen and helium produced during this phase of the universe eventually created the universe’s first massive stars.  Key steps in Stellar nucleosynthesis 1. The role of Hydrogen - Stars begin by fusing hydrogen atoms (the simplest element) into helium in their hot, dense cores. This releases a lot of energy, which makes the star shine.  Key steps in Stellar nucleosynthesis 2. Making Heavier Elements - As the star uses up its hydrogen fuel, it starts to fuse helium i n to h eav i er el emen ts l i ke carbon and oxygen. This happens in hotter parts of the core.  Key steps in Stellar nucleosynthesis 3. Layered Fusion - In very massive s tars , fu s ion c reates ev en heavier elements like neon, magnesium, and iron. Each element forms in layers, like an onion, with lighter elements fu s i n g i n ou te r l aye r s an d heavier ones closer to the core.  Key steps in Stellar nucleosynthesis 4. S t o p p i n g a t I r o n -
Fusion stops at iron because making heavier elements than iron doesn’t release energy—it actually takes energy. So, stars can’t fuse iron in their cores.  Key steps in Stellar nucleosynthesis 5. Expl os i on s Make th e R es t:
When a massive star runs out of fuel, it explodes in a s upernov a. This explos ion creates enough energy to form very heavy elements like gold and uranium.  Formative 2: (Post Activity) Match This! Match the given elements to the layer of the star where they are supposed to form. Hydrogen, Helium, Carbon, Outer Neon, Magnesium, Oxygen, Middle Silicon, Sulfur, Iron Inner  What is a life cycle? Describe the human life cycle  What is a star's life cycle? A star's life cycle is the series of stages it goes through from its formation to its eventual demise. It involves the processes of birth, adulthood, and death, which are determined by the star's mass. LIFE CYCLE OF A STAR  1. NEBULA Huge clouds of gas Some are dark shapes Others glow because the gas inside them gives off light, or starlight reflects off or passes through them. Stars begin in a nebula, a cloud of gas and dust. Gravity causes the material to clump together and form a protostar  1. NEBULA Huge clouds of gas Some are dark shapes Others glow because the gas inside them gives off light, or Credit: ESA/NASA/JPL-Caltech starlight reflects off or ▪ Nebulas are also where stars passes through them. are born. ▪ Orion Nebula above, the red stars in the lower-left corner are baby stars.  2. PROTOSTAR Protostars are huge clumps of gas and dust that aren’t quite hot enough to achieve fusion in their core. A protostar starts off looking like a cloud, but as gravity pulls it tighter and tighter together, it heats up and begins to glow. 2. PROTOSTAR Eventually the star reaches 15 million degrees Fahrenheit or ~ 8.5 million degrees Celsius, so hot that the hydrogen atoms in its core begin fusing into helium. The larger the star, the shorter the protostar stage Credit: ALMA (ESO/NAOJ/NRAO)/ Lee et al. 3. MAIN SEQUENCE Once a star begins fusion, it becomes much more stable and enters the main sequence of its life cycle. As long as it has enough hydrogen in its core to keep fusion going, a star stays in the main sequence. 3. MAIN SEQUENCE The Hertzsprung-Russell diagram shows how different stars look in different stages of their life. ▪ Developed independently in the early 1900s by Ejnar Hertzsprung and Henry Norris Russell, it plots the temperature of stars against their luminosity (the theoretical HR diagram), or the color of stars (or spectral type) against their absolute magnitude (the observational HR diagram, also known as a colour- magnitude diagram). Credit: ESO 3. MAIN SEQUENCE The Hertzsprung-Russell diagram shows how different stars look in different stages of their life. ▪ How long a star stays in the main sequence depends on its mass. ▪ The Sun is right in the middle of its main sequence. It’s four-and-a-half billion years old and will probably keep on fusing hydrogen in its core for another five billion years. Credit: ESO 3. MAIN SEQUENCE Three main region in HR diagram The main sequence stretching from the upper left (hot, luminous stars) to the bottom right (cool, faint stars) dominates the HR diagram. It is here that stars spend about 90% of their lives burning hydrogen into helium in their cores. Main sequence stars have a Morgan-Keenan Credit: ESO luminosity class labelled V. 3. MAIN SEQUENCE The Hertzsprung-Russell diagram shows how different stars look in different stages of their life. Three main region in HR diagram Red giant and supergiant stars (luminosity classes I through III) occupy the region above the main sequence. They have low surface temperatures and high luminosities which, according to the Stefan -Boltzmann law, means they also have large radii. Stars enter this evolutionary s t a g e on ce t h ey h a ve exh a u s t ed t h e Credit: ESO hydrogen fuel in their cores and have started to burn helium and other heavier elements. 3. MAIN SEQUENCE The Hertzsprung-Russell diagram shows how different stars look in different stages of their life. Three main region in HR diagram White dwarf stars (luminosity class D) are the f in al evolutionary stage of low to intermediate mass stars, and are found in the bottom left of the HR diagram. These stars are very hot but have low luminosities due to their small size. Credit: ESO 4. RED GIANT After a star runs out of hydrogen, its life changes dramatically. The star begins fusing helium into carbon instead, and this nuclear reaction makes its outer layers so hot that they begin fusing hydrogen, which expands them ▪ The reddish-orange stars Credit: ESO/G. Beccari ▪ star cluster NGC 3532 are red giants. Why are red stars cooler and blue stars hotter?  Red giants are so big, they have a much larger surface area to radiate away the energy from all the fusion going on inside them. This makes them cooler overall.  Wilhelm Wien Wien's Law states that the wavelength of peak emission is inversely proportional to the temperature of the emitting object. Significance of Wien’s Law Determining Star Colors: Hotter stars have shorter peak wavelengths, making them appear blue or white. Cooler stars emit light with longer wavelengths, making them appear red. Estimating Star Temperatures: B y m ea s u ri n g th e p ea k w a v el en g th of a s ta r's s p ec tru m , astronomers can calculate its surface temperature using the formula. Classifying Stars: Stars are classif ied into spectral types (O, B, A, F, G, K, M) based on their temperatures and colors, which correlate with Wien's law. Significance of Wien’s Law A star with a temperature of 6,000 Kelvin, what is its supposed peak wavelength? Significance of Wien’s Law  5. WHITE DWARFS White dwarfs are stars that have burned up all of the hydrogen they once used as nuclear fuel. White dwarfs are very hot at f irst, but over billions of years they cool off until they become black dwarfs and Credit: ESO no longer shine. -planetary nebula IC 5148 -blue-white  6. SUPERGIANTS They can shine up to a million times as brightly as the Sun but may only last for a million years. Their temperatures are so extreme that all kinds of fusion happens inside them. Fusion continues until the supergiant’s core becomes iron.  7. SUPERNOVAS Massive stars burn huge amounts of nuclear fuel at their cores, or centers. This produces tons of energy, so the center gets very hot. Heat generates pressure, and the pressure created by a star’s nuclear burning also keeps that star from collapsing. An illustration of one of the brightest a nd m ost e ne r ge t i c supe r nov a explosions ever recorded. Image credit: NASA/CXC/M.Weiss How do scientists study supernovas? NASA scientists Different types of telescopes NuSTAR (Nuclear Spectroscopic Telescope Array) mission, which uses X-ray vision to investigate the universe. NuSTAR is helping scientists observe supernovas and young nebulas to learn more about what happens leading up to, during, and after these spectacular blasts. An illustration of NASA’s NuSTAR spacecraft. Image credit: NASA/JPL-Caltech  If a star is massive enough (at least one-and-a-half times as massive as the Sun), its core can survive a supernova and become something very different: a neutron star or a black hole.  8. Neutron Stars Neutron stars are formed when a massive star runs out of fuel and collapses. Many neutron stars are likely undetectabl e because they si mpl y do not emi t enough radiation A neutron star is the densest object astronomers can observe directly, crushing half a million times Earth's mass into a sphere about 12 miles across, or similar in size to Manhattan Island, as shown in this illustration. (Credit: NASA's Goddard Space Flight Center)  9. BLACK HOLE Black holes are points in space that are so dense they create deep gravity sinks. Because black holes swallow all light, astronomers can't spot them di r ectl y l i ke they do the many glittery cosmic objects in the sky.  INTERMEDIATE-MASS BLACK HOLE Chandra X-ray Observatory image (in box) may be an elusive intermediate-mass black hole. Located about 32 million light-years from Earth in the Messier 74 galaxy (M74), this object emits periodic bursts of x-rays at a rate that suggests it is much larger than a stellar- mass black hole but significantly smaller than the supermassive black holes found at the centers of galaxies. P HOTO G RAP H CO URTESY NASA/CXC/U. OF MICHIGAN/J. LIU ET AL./ NOAO/AURA/NSF/T. BOROSON  REFERENCES: https://exoplanets.nasa.gov/exoplanet-catalog/7167/proxima-centauri-b/ https://www.britannica.com/place/Barnards-star https://astrobiology.nasa.gov/news/barnards-star/#:~:text=Barnard's%20star%20is%20the%20fourth, Image%20credit%3A%20NASA%20Photojournal https://www.energy.gov/science/doe-explainsnuclear-fusion-reactions#:~: text=Nuclear%20Fusion%20reactions%20power%20the,The%20leftover%20mass%20becomes%20energy. https://planetfacts.org/nucleosynthesis/ https://www.energy.gov/science/doe-explainsnucleosynthesis https://www.littlepassports.com/blog/space/the-life-cycle-of-a-star/ https://lco.global/spacebook/distance/magnitude-and-color/#:~:text=Blue%20stars%20are%20hotter%20than, than%20through%20a%20red%20filter. https://www.nationalgeographic.com/science/article/white-dwarfs https://spaceplace.nasa.gov/supernova/en/ https://imagine.gsfc.nasa.gov/science/objects/neutron_stars1.html https://www.nationalgeographic.com/science/article/black-holes PREPARED BY: MA.IVY A. DELA CRUZ