The lifecycle of a STAR!!!

get ready to take notes!

The Life of a Star…

1. Protostar- born in a nebula, gases come together and begin nuclear fusion.

2. Star- the phase where the star burns fuel. The more massive the star, the shorter it’s lifespan!

3. Red giant/supergiant- when stars run out of fuel, the outside expands and the inside contracts.

4. White Dwarf-One possible outcome. The remainder of a star, after the outer layer expands away.

5. Super Nova- If a star doesn’t become a white dwarf, it will supernova (aka- explode!)

6. Neutron Star- What’s left after a supernova (suuuuper dense core)

7. Black Hole- The most massive pre-supernova stars may become black holes after they supernova. The density reaches extreme highs and pulls everything inward to the point where light cannot even escape!

The Life of a Star…

How do stars produce light??

Stars emit TONS of energy!!

We can see some of it in the form of visible light.

When the temperature of a protostar (star beginning to form) gets hot enough Nuclear FUSION occurs.

How do stars produce light?? Stars produce light by Nuclear FUSION.

This is when two atomic nuclei combine to form a larger nucleus with a higher mass.

(ex: hydrogen becomes helium)

How stars FORM

Nebula-A large cloud in space containing dust, hydrogen gas, helium gas and plasma.

*Stars are formed in nebulae

The space between stars is called interstellar space and it contains mostly gas and dust. It’s density is extremely low- approximately 1 atom per cubic meter.

Components of Nebulae

The dust in a Nebula is not like house dust, it’s made up of much smaller particles that typically includes carbon and silicate molecules

These beautiful regions are called nebula. They are the formation of gas, dust and other materials clump together to form larger masses which attract more matter and eventually get big enough to form a star.

Here are some examples…

This picture was taken from

the Hubble Telescope, it’s called “NGC- 604” and is located in a

neighbor spiral galaxy of ours, 2.7 million light

years away from us.

Photo credit: STSci

These are the star forming “Pillars of Creation” spotted

by the Hubble Telescope.

Photo credit: STSci

Many Nebula form from the gravitational collapse of gas in the interstellar medium (ISM).

As the material collapses under it’s own weight, stars may form in the center.

Here are some examples…

Photo Credit: STSci

Some nebula are the result of supernova explosions (the death of short lived massive stars.)

Example…

This is the Crab Nebula in the

Constellation of Taurus. This Nebula is

actually visible with the naked eye on a clear

night.

Photo Credit: STSci

Some Nebula are called “Dark Nebula” and seem to be the creepers of the bunch (if you ask me), they tend to look a little more scary.

They are very dense and light has a hard time passing through (hence, they are ‘dark’)

Such as…..

This is a dark nebula called “Horse Head”It’s so dense that it obscures light from behind it.

Photo Credit: STSci

Photo Credit: STSci

And our last beauty for the day: Planetary Nebula- These are the gaseous

shells that are ejected as giant stars transform into white dwarfs.

Example…

Photo Credit: STSci

Photo Credit: STSci

Photo credit: STSci

Super Nova Remnants

Every once in a while, we get a glimpse into the beauty that is left behind after the massive explosion of a super nova (when a star explodes).

Photo Credit: STSci