The Life Cycle of the Star

By Tomasa Tucker

Before a Star is Born: Interstellar Medium

  • Matter that exists in the space between the star systems in a galaxy.

  • mostly interstellar gas (99%) and dust (1%)

  • found in between galaxies.

First Stage of a Stars Life Cycle

  • Globe of Gas producing its own heat and light by nuclear reactions called Fusion.

  • Stars are born from nebulae and consist mostly of hydrogen and helium gas.

  • There are colors from red to blue-white.

  • Live for less than a million years before exploding as supernovae

  • The faintest stars are the red dwarfs,


  • Object are exactly balanced,

  • Gravity causes each force

The Birth of a Star

  • Astronomers think that a star begins to form as a dense cloud of gas in the arms of spiral galaxies.

  • The first sign of a star's old age is a swelling and reddening of its outer regions.

  • exhausted, a star cannot generate sufficient pressure at its center to balance the crushing force of gravity.

  • Later in the history of the galaxy, other stars are formed out of this mixture.

  • The Hubble Space Telescope has observed more than 200 huge star clusters, giving scientists a glimpse of what occurred when the universe was young.

Second Phase of a Stars Life Cycle

  • The elements that make up a star is hydrogen and helium

  • During this phase the the star is basically recycled then made into another star.

  • Determination on the star it all depends on how good the star is, how healthy the star is

  • At the end the star dies then is reborn

Third Phase of a Star’s life cycle

  • The phase of the star is called Stellar evolution

  • Nebulae and molecule clouds make up a star

  • During this phase the star starts to cluster

  • Violent explosions of older stars create shock waves during this nuclear phase

  • The properties of a star during this phase are (luminosity, temperature, volume) and it starts to decrease

Final Phase of a Star’s Life Cycle

  • A star dies Several billion years after its life starts

  • It happens when the core runs out of hydrogen fuel, it will die down under the weight of gravity

  • The possible ways in which a star dies is the core will become hot enough to cause the helium to fuse into carbon. When the helium fuel runs out, the core will expand and cool

  • What determines the way a star dies is when the core contracts, it heats up. This heats the upper layers, causing them to expand

  • A supernova produces when the star gets old

  • When a planetary nebula produces its upper layers will expand and eject material that will collect around the dying star to form a planetary nebula

The Role of Star’s Light

  • composition is when the star reveals lights about its composition the astronauts see visual light flash activity

  • a star’s light become red-shifted or blue-shifted when Sound or light waves emitted by the object are stretched out, which makes them have a lower pitch and moves them towards the red end of the electromagnetic spectrum.

  • Star’s light can be used as an example of the Doppler effect, effect observed in light and sound waves as they move toward or away from an observer.

The Origin of the Elements

  • Elements come from space and time were created in the Big Bang,

  • happened 13.7 billion years ago, the universe was a very hot expanding are covered with particles

  • Hydrogen, nitrogen, iron, and, oxygen first group of compounds that formed into chemicals of life.