Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
SlideShare a Scribd company logo

Life cycle of a star

•Download as PPTX, PDF•
•
O
OM BIKASH DAS

This document discusses the life cycle of stars from their formation to their death. It begins by explaining that stars are giant balls of exploding gas made up mainly of hydrogen and helium. The document then outlines the various stages of a star's life: nebula, protostar, main sequence star, red giant, white dwarf, supernova, neutron star, and black hole. For each stage, it provides a brief description of the physical changes occurring within the star. The document emphasizes that stars much more massive than our sun will end their lives as neutron stars or black holes through the supernova process.

1 of 16
Prepared By - OM BIKASH DAS Roll no - PH1217 Msc Physics in BERHAMPUR UNIVERSITY
 Stars are essentially giant balls of exploding gas, which mainly consists of hydrogen and helium. The nearest star to Earth, the Sun, is constantly explodingin a nuclear reaction with the element hydrogen,which makes the explosion similar to a hydrogenbomb. These nuclear reactions are constantlyreleasing energy into the universe, along with solarwinds and solar flares (QRG, n.d.). The onlyprotection the earth has from the solar winds andflares is the magnetic field surrounding the Earth(Association, N. E. (n.d.). What is a Star ?
 Nebula  Proto star  Main sequence star  Red Giant  White Dwarf  Supernova  Neutron Star  Black Hole
 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 heals up and is known as a protostar .
 The second stage of star creation .  At this point the temperature eventually reaches 15,000,000°C and nuclear fusion occurs in the clouds core  The cloud begins to glow brightly .  At this stage, it contracts a little and becomes stable and is called a main sequence star .
 A star will remain in this stage, shining for millions or billions of year to come .  As the main sequence star glows, hydrogen in the core is converted into helium by nuclear reaction .  Our Sun is a main sequence star, Although the sun is extremely large compared to Earth, it is only a medium- sized star .
 When the hydrogen supply in the core begins 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 .  All star evolve the same way up to the red giant phase; the amount of mass a star has determines which of the following life cycle paths it will take after the red giant phase .
 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 .  Once all their energy is gone, they no longer emit light  The star has now reached the black dwarf phases in which it will forever remain  This is the last stage in the life cycle of a star
 Once massive starts 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 powerful explosion called as supernova .
 A Supernova is the explosive death of a star, that often results in the star obtaining the brightness of 100 million suns for a short time. There are two main types of Supernova which will occure:-  Type I - The fist type of Supernova will occur in binary star systems. As a result the gas from one star will fall on to a white dwarf, in turn causing it to explode .  Type II - The second type will occur in stars which are ten times larger than our own star. These are known as Super-Giant Stars. When the Stars nuclear fuel is exhausted the iron core will collapse and then rebound, creating a massive explosion .
 The core of a massive star that us 1.5 to 4 times as larger as our Sun ends up as a neutron star after the supernova  Neutron stars spin rapidly giving of radio waves if the radio waves are emitted in pulses(due to the star‘s spin), the neutron star is called a pulsar
 No nuclear fusion is taking place to support the core, so it is allowed by it own gravity  It has now become a black hole which readily attracts any matter and energy that comes near it  The core of a massive star that has 8 or more times the mass of our Sun remains massive after the supernova  Black holes are not visible they are detected by the X- ray which are given off as matter falls into the hole
Life cycle of a star
Life cycle of a star
Life cycle of a star
THANK YOU …

More Related Content

Life cycle of a star

  • 1. Prepared By - OM BIKASH DAS Roll no - PH1217 Msc Physics in BERHAMPUR UNIVERSITY
  • 2.  Stars are essentially giant balls of exploding gas, which mainly consists of hydrogen and helium. The nearest star to Earth, the Sun, is constantly explodingin a nuclear reaction with the element hydrogen,which makes the explosion similar to a hydrogenbomb. These nuclear reactions are constantlyreleasing energy into the universe, along with solarwinds and solar flares (QRG, n.d.). The onlyprotection the earth has from the solar winds andflares is the magnetic field surrounding the Earth(Association, N. E. (n.d.). What is a Star ?
  • 3.  Nebula  Proto star  Main sequence star  Red Giant  White Dwarf  Supernova  Neutron Star  Black Hole
  • 4.  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 heals up and is known as a protostar .
  • 5.  The second stage of star creation .  At this point the temperature eventually reaches 15,000,000°C and nuclear fusion occurs in the clouds core  The cloud begins to glow brightly .  At this stage, it contracts a little and becomes stable and is called a main sequence star .
  • 6.  A star will remain in this stage, shining for millions or billions of year to come .  As the main sequence star glows, hydrogen in the core is converted into helium by nuclear reaction .  Our Sun is a main sequence star, Although the sun is extremely large compared to Earth, it is only a medium- sized star .
  • 7.  When the hydrogen supply in the core begins 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 .  All star evolve the same way up to the red giant phase; the amount of mass a star has determines which of the following life cycle paths it will take after the red giant phase .
  • 8.  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 .  Once all their energy is gone, they no longer emit light  The star has now reached the black dwarf phases in which it will forever remain  This is the last stage in the life cycle of a star
  • 9.  Once massive starts 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 powerful explosion called as supernova .
  • 10.  A Supernova is the explosive death of a star, that often results in the star obtaining the brightness of 100 million suns for a short time. There are two main types of Supernova which will occure:-  Type I - The fist type of Supernova will occur in binary star systems. As a result the gas from one star will fall on to a white dwarf, in turn causing it to explode .  Type II - The second type will occur in stars which are ten times larger than our own star. These are known as Super-Giant Stars. When the Stars nuclear fuel is exhausted the iron core will collapse and then rebound, creating a massive explosion .
  • 11.  The core of a massive star that us 1.5 to 4 times as larger as our Sun ends up as a neutron star after the supernova  Neutron stars spin rapidly giving of radio waves if the radio waves are emitted in pulses(due to the star‘s spin), the neutron star is called a pulsar
  • 12.  No nuclear fusion is taking place to support the core, so it is allowed by it own gravity  It has now become a black hole which readily attracts any matter and energy that comes near it  The core of a massive star that has 8 or more times the mass of our Sun remains massive after the supernova  Black holes are not visible they are detected by the X- ray which are given off as matter falls into the hole