Life cycle of stars

Interstellar Medium

What is it? the space between stars

What is it made up of?mostly gas and some dust

Where is it? In space


1. Identify the first stage of a star’s life cycle

What elements are present in this stage?

Describe this stage

Hydrogen, This is when the star starts to form.


Equilibrium is established

define equilibrium a state when opposite forces are equal

what two forces are in balance in this particular equilibrium?

What causes each force?

Which force pushes inward? gravity

Which force pushes outward? presser.


The Birth of a Star

After equilibrium is established, a certain nuclear process begins.

What is this process? fusion

Define this process.when 2 particles are smashed together

What causes this process to begin?

Give an equation for the process that occurs specifically in stars. Identify starting materials and products


2. Identify the second phase of a star’s life cycle

What is this phase called?main

What elements make up a star during this phase?hydrogen and some helium

What happens during this phase?

What determines how long (or whether) a star will be in this phase?34 billion years

What happens at the end of this phase, in terms of nuclear processes? the processes turns to fission

3. Identify the third phase of a star’s life cycle

What is this phase called? dying phase

What elements make up a star during this phase? heliom

What happens during this phase? The star compress it self and becomes smaller

What nuclear processes occur during this phase?fission and fusion

What happens to the properties of a star during this phase (luminosity, temperature, volume) they all decrease


4. Identify the final phase of a star’s life cycle

When does a star die? when it runs out of hydrogen Why does this happen? because it burns though it all

What are the possible ways in which a star dies? explodes into a nebula or turn into a black hole What determines the way in which a star dies?

When is a supernova produced? What is this?

When is a planetary nebula produced? What is this?


The Role of Star’s Light

What does a star’s light reveal about its composition? Give an example.

How does a star’s light become red-shifted or blue-shifted? What does this mean?

How could a star’s light be used as an example of the Doppler effect?


The Origin of the Elements

Where do the elements come from?

Give specific examples for hydrogen, iron, nitrogen, and oxygen. The elements come from stars but are brought to earth from asteroids.