Life cycle of stars
description
Transcript of Life cycle of stars
![Page 1: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/1.jpg)
Life cycle of stars
![Page 2: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/2.jpg)
• During the collapse, the material heats up by frictional processes and begins to radiate infra-red radiation so astronomers are hoping to detect this to confirm the formation process. This is very difficult because the protostar would have a lot of gas and dust still surrounding it (a Bok Globule).• Stars are formed in groups as the different parts of the original nebula collapse.
![Page 3: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/3.jpg)
Travelling at the speed of light (or radio wave)300,000 km /sec
8 minutes
6 hours
4 years
sun
nearest star
pluto
![Page 4: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/4.jpg)
100,000 light years
100 billion stars
Milky way galaxyAndromeda galaxy
Our sun is one of millions of stars in a group of stars called a galaxy
![Page 5: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/5.jpg)
100,000 light years
100 billion stars
Light from our nearest galaxy has taken 2 million years to reach us!
Milky way galaxyAndromeda galaxy
Our sun is one of millions of stars in a group of stars called a galaxy
![Page 6: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/6.jpg)
BIRTH OF A STAR
* A star forms from a huge cloud of dust and gas.
* Gravity slowly pulls the material together.
* Rocks crash into each other and heat up.
Our sun 4,500 million years ago.
• During the collapse, the material heats up by frictional processes and begins to radiate infra-red radiation so astronomers are hoping to detect this to confirm the formation process.
![Page 7: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/7.jpg)
BIRTH OF A STAR
* A star forms from a huge cloud of dust and gas.
* Gravity slowly pulls the material together.
* Rocks crash into each other and heat up.
Our sun 4,500 million years ago.
* Nuclear reactions begin and the star starts to shine.
![Page 8: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/8.jpg)
Our sun 4,500 million years ago.
BIRTH OF A STAR
Planets are natural satellites
of the sun * Smaller masses cool to form planets which orbit the sun under gravity.
* During a star’s life time, nuclei of lighter elements (mainly hydrogen and helium ) fuse to produce nuclei of heavier elements
* Nuclear reactions begin and the star starts to shine.
![Page 9: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/9.jpg)
THE HERTZSPRUNG - RUSSELL DIAGRAM
LIGHT
INTENSITY
Wave length of light emittedBlue Red
HOT Cold
Newly formed stars join the ‘main sequence’at a point on the graph that relates to its mass.
![Page 10: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/10.jpg)
THE STABLE LIFE OF A STAR
![Page 11: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/11.jpg)
THE STABLE LIFE OF A STAR
![Page 12: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/12.jpg)
THE STABLE LIFE OF A STAR
- Our sun stays on main sequence for 10 billion years
- If star mass is 15 x suns mass
then 10 million years.
Stars of greater mass than our sun (have higher core temperatures)can fuse heavier elements up to iron releasing even more energy.
![Page 13: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/13.jpg)
![Page 14: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/14.jpg)
![Page 15: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/15.jpg)
![Page 16: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/16.jpg)
![Page 17: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/17.jpg)
![Page 18: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/18.jpg)
![Page 19: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/19.jpg)
Dark matter (ash)
![Page 20: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/20.jpg)
![Page 21: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/21.jpg)
Super nova
![Page 22: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/22.jpg)
Explosionfusing heaviestknown elementseg 92U
![Page 23: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/23.jpg)
Explosionfusing heaviestknown elementseg 92UalsoNew young starsand condensing
planets may form
![Page 24: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/24.jpg)
![Page 25: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/25.jpg)
![Page 26: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/26.jpg)
Neutron star:p + e n v. dense !
![Page 27: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/27.jpg)
Neutron star:p + e n v. dense !
![Page 28: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/28.jpg)
For very massive stars, the material is so dense,the force of gravity so strong , that light itself cannot escape.
![Page 29: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/29.jpg)
![Page 30: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/30.jpg)
Nebular
Protostar Main Sequence
star
Red giantWhite dwarf
P3 4.2 The life history of a star similar in size to our sun
Protostar Gravity draws atoms together, releasing energy star heats up but does not shine,
Gravity draws atoms together, releasing energy Nebular
The star shines during fusion of hydrogen to helium for billions of years; outward radiation pressure is balanced by inward pull of gravity.
Star
Red giant Most of Hydrogen has been used, now helium fuses to make carbon, unused hydrogen is ejected to the surface, cools and appears red.
White dwarf Fusion stops, gravitational collapse occurs, star heats up and changescolour from red to yellow to white. It finally becomes cold dark matter.
![Page 31: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/31.jpg)
Nebular
Protostar Main Sequence
star
Red giantWhite dwarf
P3 4.2 The life history of a star similar in size to our sun
Protostar Gravity draws atoms together, releasing energy star heats up but does not shine,
Gravity draws atoms together, releasing energy Nebular
The star shines during fusion of hydrogen to helium for billions of years; outward radiation pressure is balanced by inward pull of gravity.
Star
Red giant Most of Hydrogen has been used, now helium fuses to make carbon, unused hydrogen is ejected to the surface, cools and appears red.
White dwarf Fusion stops, gravitational collapse occurs, star heats up and changescolour from red to yellow to white. It finally becomes cold dark matter.
![Page 32: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/32.jpg)
Nebular
Protostar Main Sequence
star
Red giantWhite dwarf
P3 4.2 The life history of a star similar in size to our sun
Protostar Gravity draws atoms together, releasing energy star heats up but does not shine,
Gravity draws atoms together, releasing energy Nebular
The star shines during fusion of hydrogen to helium for billions of years; outward radiation pressure is balanced by inward pull of gravity.
Star
Red giant Most of Hydrogen has been used, now helium fuses to make carbon, unused hydrogen is ejected to the surface, cools and appears red.
White dwarf Fusion stops, gravitational collapse occurs, star heats up and changescolour from red to yellow to white. It finally becomes cold dark matter.
![Page 33: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/33.jpg)
Nebular
Protostar Main Sequence
star
Red giantWhite dwarf
P3 4.2 The life history of a star similar in size to our sun
Protostar Gravity draws atoms together, releasing energy star heats up but does not shine,
Gravity draws atoms together, releasing energy Nebular
The star shines during fusion of hydrogen to helium for billions of years; outward radiation pressure is balanced by inward pull of gravity.
Star
Red giant Most of Hydrogen has been used, now helium fuses to make carbon, unused hydrogen is ejected to the surface, cools and appears red.
White dwarf Fusion stops, gravitational collapse occurs, star heats up and changescolour from red to yellow to white. It finally becomes cold dark matter.
![Page 34: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/34.jpg)
Nebular
Protostar massivestar Super red
giantSuper nova
P3 4.2 The life history of a star several times larger than our sun
The explosion compresses the core into very densely packed neutrons. If the original star was more massive a black hole would be created. (The gravitational field is so strong that not even light can escape from it.)
Fusion stops, gravitational collapse occurs, star heats up and changes colour from red to yellow to white. After further collapse it explodes as a supernova! (Outshines a galaxy for several weeks)
Neutron Star:
Super Nova:
White dwarf
![Page 35: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/35.jpg)
Nebular
Protostar massivestar Super red
giantSuper nova
P3 4.2 The life history of a star several times larger than our sun
The explosion compresses the core into very densely packed neutrons. If the original star was more massive a black hole would be created. (The gravitational field is so strong that not even light can escape from it.)
Neutron Star:
Fusion stops, gravitational collapse occurs, star heats up and changes colour from red to yellow to white. After further collapse it explodes as a supernova! (Outshines a galaxy for several weeks)
Super Nova:
White dwarf
![Page 36: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/36.jpg)
![Page 37: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/37.jpg)
![Page 38: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/38.jpg)
![Page 39: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/39.jpg)
![Page 40: Life cycle of stars](https://reader035.fdocuments.in/reader035/viewer/2022062518/56814099550346895dac392c/html5/thumbnails/40.jpg)