Life Cycle Of A Star - Tanmayee Bharadwaj

LIFE cycle of a star

from start to finish!

By : Tanmayee Bharadwaj

Table of contents

supernova

White dwarf

protostar

black hole

nuclear fusion

Black dwarf

Low mass star

high mass star

neutron star

Red Giant

thank you

supergiant

protostar!

The first stage! WOW!

protostars and nebulae

What are they and how do they form?

Nebulae are clouds of dust and gas that have formed due to the gravity of small particles in space attracting to each other. They are also sometimes referred to as star nurseries. The gravity that made the cloud will eventually push together even more and create a protostar, the first stage of the life cycle of a star!

low mass star

What is a low mass star?

Low mass star

What is it and how does it form?

A low mass star is when a protostar becomes a main-sequence star, and the process of hydrogen fusion (hydrogen fusing into helium) begins. This stage is the longest and can last up to billions of years. The life cycle of a star depends on the mass, so low mass stars have very different life cycles than high mass stars.

red giant!

Why do we call it the red giant?

a red giant

What are they and how do they form?

A red giant star is the second stage in a low mass star life cycle. When the process of hydrogen fusion is coming to an end, the balance of pressure is disturbed, so the inward forces are stronger. The star's core, therefore, shrinks rapidly. When a fresh shell of hydrogen surrounds the core, the gravity pushing in on it increases the heat as to where hydrogen fusion can take place once again. Because the outward forces are now stronger than the inward forces, the star becomes larger and brighter, and gets the name "Red Giant". It is red because the star isn't as hot as it was before, and the redder a star is the hotter it is.

white dwarf

(And maybe black dwarf)

a white dwarf

What is it and how does it form?

A white dwarf is the last (scientifically proven) stage in the life cycle of a low mass star. As time goes noon, the outer layers of the red giant start to come away, leaving shaped clouds of gas around the star. The clouds thinning away is the cue for gravity to push inward, which causes the star's core to collapse. The core becomes denser, hotter, and brighter. This is then called a white dwarf. One white dwarf star is very small in size, about the size of the Earth. Shining for billions of years before cooling completely, this stage in a low mass star's life cycle is not theoretically the last stage. Scientifically yes, but many think that after millions of billions of years, a white dwarf will cool completely leaving only the mass of it, no radiation, light, or heat. However, our universe is still too young for this, and moreover, this is only just a theory.

high mass star!

What's the difference?

high mass star

What is it and how is it formed?

A high mass star is very similar to a low mass star-- the only difference is the fact that it has much more mass. The process of hydrogen fusion is the same for a high mass star as well. The stages that come after however are very different.

supergiant

Wow! A supergiant!

Supergiant

What is it and how it is formed?

A supergiant is the next stage in a high mass star's life cycle. Fusions that involve nuclei turning in to heavier elements than carbon. This star will then become a supergiant because the time it takes for high mass stars to become supergiants is much shorter than the time it takes low mass stars to become red giants.

supernova

EXPLOSION!

supernova

What is it and how does it form?

The next stage in a high mass star life cycle is a supernova. In the supergiant stage, the high-mass star has nuclei fuel that it has to use. Once this is all up, the energy that prevented it from collapsing is gone, so the star collapses on its core. An enormous amount of energy is then released, first causing the collapsing to stop and then resulting in a supernova, an explosion in which the outer layers of a star are pushed into space and only the core remains.

black hole

WOW! Pure black in space?

a black hole

What is it and how does it form?

A black hole is one thing that can happen to a supergiant after it supernovas. Because the star is so massive, the core continues to collapse under its own gravity. As the core collapses, the gravity becomes greater, until it is brought to a tiny, invisible point. Not even light can escape the gravity of this point, but scientists are able to track it because of the radiation the swirling objects around it before going into the point emit, some even in our galaxy!

Neutron star

Intersting!

neutron stars

What are they and how do they form?

Neutron stars are formed with less massive stars, but are just as important. When the core collapses further on its core, the electrons and protons smash together to form neutrons, resulting in an incredibly dense star. A neutron star of only 20 kilometers can emit the energy of 100,000 suns! WOW! These neutron stars also rotate very rapidly, and anytime one that emits an electromagnetic beam comes to the Earth, scientists can track and trace it. These are called pulsars.

THANK you!

I hope you have learned more about stars, and have entered into a new universe of learning!