Stars go through a natural cycle, much like any living beings. This cycle begins with birth, expands through a lifespan characterized by change and growth, and ultimately leads to death. The time frame in the life cycle of stars is entirely different from the life cycle of a living being, lasting in the order of billions of years. In this piece of article, let us discuss the life cycle of stars and its different stages. Stars come in a variety of masses and the mass determines how radiantly the star will shine and how it dies. Massive stars transform into supernovae, neutron stars and black holes while average stars like the sun, end life as a white dwarf surrounded by a disappearing planetary nebula. All stars, irrespective of their size, follow the same 7 stage cycle, they start as a gas cloud and end as a star remnant. A star originates from a large cloud of gas. The temperature in the cloud is low enough for the synthesis of molecules. The Orion cloud complex in the Orion system is an example of a star in this stage of life. When the gas particles in the molecular cloud run into each other, heat energy is produced. This results in the formation of a warm clump of molecules referred to as the Protostar. The creation of Protostars can be seen through infrared vision as the Protostars are warmer than other materials in the molecular cloud. Several Protostars can be formed in one cloud, depending on the size of the molecular cloud. A T-Tauri star begins when materials stop falling into the Protostar and release tremendous amounts of energy. The mean temperature of the Tauri star isn’t enough to support nuclear fusion at its core. The T-Tauri star lasts for about 100 million years, following which it enters the most extended phase of development – the Main sequence phase. The main sequence phase is the stage in development where the core temperature reaches the point for the fusion to commence. In this process, the protons of hydrogen are converted into atoms of helium. This reaction is exothermic; it gives off more heat than it requires and so the core of a main-sequence star releases a tremendous amount of energy. A star converts hydrogen atoms into helium over its course of life at its core. Eventually, the hydrogen fuel runs out, and the internal reaction stops. Without the reactions occurring at the core, a star contracts inward through gravity causing it to expand. As it expands, the star first becomes a subgiant star and then a red giant. Red giants have cooler surfaces than the main-sequence star, and because of this, they appear red than yellow. Helium molecules fuse at the core, as the star expands. The energy of this reaction prevents the core from collapsing. The core shrinks and begins fusing carbon, once the helium fusion ends. This process repeats until iron appears at the core. The iron fusion reaction absorbs energy, which causes the core to collapse. This implosion transforms massive stars into a supernova while smaller stars like the sun contract into white dwarfs. Most of the star material is blasted away into space, but the core implodes into a neutron star or a singularity known as the black hole. Less massive stars don’t explode, their cores contract instead into a tiny, hot star known as the white dwarf while the outer material drifts away. Stars tinier than the sun, don’t have enough mass to burn with anything but a red glow during their main sequence. These red dwarves are difficult to spot. But, these may be the most common stars that can burn for trillions of years. The above were the seven main stages of the life cycle of a star. Whether big or small, young or old, stars are one of the most beautiful and lyrical objects in all of creation. Next time you look up at the stars, remember, this is how they were created and how they will die. Did you know that some of the stars we see in the sky may already be dead! Their light travels millions and millions of kilometres, and by the time it reaches us, the star would have died. So the distance between our planet and the stars further away is unimaginable, but measurable still. Watch and learn how these distances can be measured and the secrets hiding among the stars.  To learn more Physics concepts with the help of interactive video lessons, download BYJU’S – The Learning App.
Yes, stars do die once they complete their lifecycle.
Different stages of life cycle of stars are:
This process takes place in the red giant stage.
Nuclear fusion reaction takes place inside the star.
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out of 0 arewrong out of 0 are correct out of 0 are Unattempted View Quiz Answers and AnalysisGravity and nuclear fusion reactions drive the formation and development of stars. Stars with different masses grow and change throughout the different stages of their lives.
The life cycle of the Sun began roughly 4.6 billion years ago and will continue for almost another 8 billion years when it will have depleted its supply of nuclear fuel and collapse into a white dwarf. The Sun and all our planets in the solar system began as a giant cloud of molecular gas and dust. Then, about 4.5 billion years ago the cloud collapsed. From this collapse, dust and gas began to collect into denser regions. As the regions pulled in more matter, conservation of angular momentum caused it to begin rotating while increasing pressure caused it to heat up. Most of the material ended up in a ball at the center while the rest of the matter flattened out into a disk that circled around it. The ball at the center would eventually form the Sun while the disk of material would form the planets. The Sun spent about 100,000 years as a collapsing protostar before temperatures and pressures in the interior ignited fusion at its core. And just a few million years later, it settled down into its current form. The life cycle of the Sun has now begun. The Main Sequence StageLike most stars in our universe, the Sun is on the main sequence stage of its life. This means nuclear fusion reactions in its core fused hydrogen into helium. However, this process cannot last forever since there is a finite amount of hydrogen in the core of the Sun. Currently it has more than 72% hydrogen. One billion years from now, the Sun will be 10% brighter than it currently is. This will trigger a moist greenhouse effect here on Earth that is similar to the hellish Venus environments that we see today. Under these conditions, life as we know it will be unable to survive anywhere on the surface of Earth.
One day in the distant future the Sun will run out of hydrogen fuel. This will begin in approximately 6.4 billion years at which point the Sun will exit the main sequence stage of its life. With its hydrogen exhausted in the core, its inner helium ash that has built up there will become unstable and collapse under its own weight. The helium outside its core will start to fuse in a shell around the dead core. Then, our star will enter the red giant phase and swell up much faster. It is calculated that the expanding Sun will grow large enough to encompass the orbits of Mercury, Venus, and maybe even Earth. Death of the SunAll things must end. When people think of stars dying, what typically comes to mind are massive supernovas and the creation of black holes. However, this will not be the case with our Sun due to the fact that it is simply not massive enough. About one billion years after the Sun tries to swallow Earth, the red giant will undergo a process called Helium flash where huge amounts of Helium is fused to Carbon in a matter of minutes. Once the Helium in the core starts fusion, the star will then shrink but gain luminosity. Over the course of the next 20 million years, the Sun will then become unstable and begin losing mass through a series of thermal pulses. These powerful bursts of radiation will cause the Sun to fling wave after wave of material out into space. After about 500,000 years of these stellar tantrums, the Sun will have tossed away half of its mass. That discarded material will briefly form a beautiful planetary nebula. The remnant will eventually cool and become a white dwarf which is mostly made up of just carbon and oxygen. This smoldering ember will glow for trillions of years before fading to black. Imagine being from another world, another civilization, far off in some other system like our own witnessing the Sun’s life cycle. It would look like so many mesmerizing stars and the stages that they go through, that we ourselves wonder and gaze upon. In the meantime, however, we have many days ahead of us filled with sunshine to look forward to. One thing is for sure, and that is that we must continue marching onwards because the universe, let alone the Sun, will not be slowing down for us to catch up.
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