Introduction

This diagram was designed as a way to cover the basics of stars and their lives. Some stars may live for 10 or more giga years while others will only live for a few million. The life of a star is a balancing act between the internal reactions and the gravity of its mass. It all begins in a cloud of gas and dust.

1 Gas & Dust Cloud

Stars are born from molecular clouds made up of dust and gasses, mostly hydrogen. As the particles gather from their graviational pulls areas of condensed gasses form. This new star forming is called a protostar.

2 Entering Main Sequence

Here the star is burning hydrogen through fusion as it cools it shrinks slighltly and enters it's middle and longest age of life.

Brown Dwarfs

Brown dwarfs are stars that never grew massive enough to begin fusion of hydrogen. They do omit some energy however due to the gravitational collapse of the particles within them. Though they aren't quite stars they also aren't planets.

Main Sequence

The longest portion of a star's life is the main sequence, where all stars are burning mostly hydrogen into helium. The larger the star the shorter its main sequence life is.

If you were to squeeze our sun's life into the life of a human's with 1 year equaling 1/5th of a second, the sun's main sequence life would be 60 years long!

Red Giant Phase

As the sun continues to burn hydrogen it gradually increases in size until it uses up the hydrogen in the core. The reactions contnue in the shell of the star and it begins to rapidly expand. It becomes a red giant.

4Helium Flash

The helium flash occurs after the star has collapsed on itself a bit. At this point the core is hot enough to begin burning helium. More massive stars can begin burning larger elements such as carbon, oxygen and neon, all the way up till iron.

After the helium flash the star continues burning similar to its main sequence state, now converting helium to carbon until the helium runs out. Again the core's fuel is depleated and the planet expands once more.

5Planetary Nebula

After a star of 0.5 to 8 solar masses has spent its helium it becomes unstable. There isn't a strong enough gravity to hold the reactions in. The star begins to burst with energy randomly at a rapid rate and the shell is blown off into space. This is called a planetary nebula.

6Novae

Stars of larger masses explode with a stronger force, increasing in brightness up to 50,000 times it's red giant levels. View a novae. What's left behind is usually a neutron star.

BBinary Systems

Binary systems are not uncommon in the galaxy and it is common for a dying star, such as a white dwarf to feed off a neighbor that has expanded near it's gravitational boundaries. As the material from the neighboring star accumulates onto the white dwarf reactions begin again and the star expands an explodes in a novae.

7Supernovae

Stars even larger release an extrodinary amount of energy when they explode. More than 100,000 times that of a novae leaving behind a neutron or sometimes even a black hole. View a supernovae.

ABlack Holes

Very massive stars explode with such violence that what remains after the explosion is not strong enough to resist the star's gravitational pull. The collapse cannot be stopped and the star will continue to decrease in volume until it reaches zero also known as the singularity. The star becomes so dense that not even light can escape its gravitational pull.

Neutron / White Dwarf
A Star's Death

White Dwarfs
An average star like our sun's lives out its final days as a white dwarf. No new energy is being manufactured and the star, now about the size of the Earth glows from stored thermal energy. Once the star finally cools it becomes a black dwarf.

Netron Stars
More massive stars colapse even further, the pressure is so strong that even electrons and protons combine to form neutrons, which give this star its name. The diameter is usually incredibly small; only 10 to 20 km across!