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The life cycle of a star

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Nelson Correia
Nelson Correia

The document outlines the life cycle of stars from birth in nebulae of gas and dust through their main sequence phase, later evolution into red giants, and final stages as white dwarfs, neutron stars, or black holes. It describes how gravity pulls gas together in nebulae to form protostars, which become main sequence stars fueling nuclear fusion for millions of years. As hydrogen runs out in their cores, more massive stars explode as supernovae while lower mass stars expand into red giants then contract into white dwarfs.

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The Life Cycle of a star By Ramunė Stabingytė and Kotryna Bieliauskaitė Kaunas “Vyturys” cathalic secondary school
The life cycle of a star
Birth of a star • In space, there are huge clouds of gas and dust called nebulas. • These clouds are made up of hydrogen and helium and are the birthplace of new stars. • Gravity pulls the hydrogen gas in the nebula together and it begins to spin, • As the gas spins faster and faster, it heats up and is known as a protostar.
Protostar • The second stage of star creation. • At this point the temperature eventually reaches 15,000,000 °C. • The cloud begins to glow brightly. • At this stage, it contracts a little and becomes stable and is called a main sequence star.
Main sequence star • A star will remain in this stage, shining for millions or billions of years to come. • As the main sequence star glows, hydrogen in the core is converted into helium by nuclear reactions. • Our sun is a main sequence star.
Red giant phase • When the hydrogen supply in the core begin to run out, the core becomes unstable and contracts. • The outer shell of the star starts to expand. • As it expands, it cools and glows red. • The star has now reached the red giant phase.
White dwarfs • Gravity causes the last of the star’s matter to collapse inward and compact, this is the white dwarf stage. • At this stage the star’s matter is extremely dense. • White dwarfs shine with a white hot light. • The star has now reached the black dwarf phase in which it will forever remain.
Massive stars • Once massive stars reach the red giant phase, the core temperature increases. • Gravity continues to pull carbon atoms together as the temperature increases forming oxygen, nitrogen, and eventually iron. • At this point, fusion stops and the iron atoms start to absorb energy. • This energy is eventually released in a powerful explosion called a supernova.
Supernova • A supernova can light up the sky for weeks. • The temperature in one can reach 1,000,000,000 °C. • The supernova then either becomes a neutron star or a black hole.
The life cycle of a star
Neutron star • Neutron stars spin rapidly giving of radio waves. • If the radio waves are emitted in pulses, the neutron star is called a pulsar.
Black hole • The core of a massive star that has 8 or more times the mass of our Sun remains massive after the supernova. • It has now become a black hole which readily attracts any matter and energy that comes near it. • Black holes are not visible, they are detected by the X- rays which are given off as matter falls into the hole.
The life cycle of a star
The life cycle of a star

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The life cycle of a star

  • 1. The Life Cycle of a star By Ramunė Stabingytė and Kotryna Bieliauskaitė Kaunas “Vyturys” cathalic secondary school
  • 3. Birth of a star • In space, there are huge clouds of gas and dust called nebulas. • These clouds are made up of hydrogen and helium and are the birthplace of new stars. • Gravity pulls the hydrogen gas in the nebula together and it begins to spin, • As the gas spins faster and faster, it heats up and is known as a protostar.
  • 4. Protostar • The second stage of star creation. • At this point the temperature eventually reaches 15,000,000 °C. • The cloud begins to glow brightly. • At this stage, it contracts a little and becomes stable and is called a main sequence star.
  • 5. Main sequence star • A star will remain in this stage, shining for millions or billions of years to come. • As the main sequence star glows, hydrogen in the core is converted into helium by nuclear reactions. • Our sun is a main sequence star.
  • 6. Red giant phase • When the hydrogen supply in the core begin to run out, the core becomes unstable and contracts. • The outer shell of the star starts to expand. • As it expands, it cools and glows red. • The star has now reached the red giant phase.
  • 7. White dwarfs • Gravity causes the last of the star’s matter to collapse inward and compact, this is the white dwarf stage. • At this stage the star’s matter is extremely dense. • White dwarfs shine with a white hot light. • The star has now reached the black dwarf phase in which it will forever remain.
  • 8. Massive stars • Once massive stars reach the red giant phase, the core temperature increases. • Gravity continues to pull carbon atoms together as the temperature increases forming oxygen, nitrogen, and eventually iron. • At this point, fusion stops and the iron atoms start to absorb energy. • This energy is eventually released in a powerful explosion called a supernova.
  • 9. Supernova • A supernova can light up the sky for weeks. • The temperature in one can reach 1,000,000,000 °C. • The supernova then either becomes a neutron star or a black hole.
  • 11. Neutron star • Neutron stars spin rapidly giving of radio waves. • If the radio waves are emitted in pulses, the neutron star is called a pulsar.
  • 12. Black hole • The core of a massive star that has 8 or more times the mass of our Sun remains massive after the supernova. • It has now become a black hole which readily attracts any matter and energy that comes near it. • Black holes are not visible, they are detected by the X- rays which are given off as matter falls into the hole.