WHITE DWARF The first white dwarf was discovered in 1844, by Fredrich Bessel. While he was observing Sirius, he noticed that it was moving back and forth, like it was orbiting something. Later on in 1863, an optician and telescope maker by the name of Alvan Clark noticed something odd, while observing Sirius. It was found to be a white dwarf. Later it was called Sirius B, being the white dwarf. White dwarfs are like most other stars; however they are not as bright and smaller. They are extremely dense and very hard to detect.
They are the same size as Earth, but smaller then the Sun, and have the same weight. The heavier the white dwarf is, the smaller its size will be. They received their name because of the white color of the first ones that were discovered. The white dwarfs represent a final stage of the stars life cycle, similar to the sun. They are formed when the stars use up the chemicals that is used to fuel fire; They need to use up most of its nuclear fuel in its main sequence stage, or move through a giant stage. They can shed any remaining fuel in its outer layer by leaving only a glowing substance.
Many white dwarfs are what stars like our Sun will become after they have burned. Once the star burns out completely or stops radiating, that’s when the white dwarf will be in its final stage of change. Near the end of their life, the star will go through 4 stages before it will become a white dwarf. The first stage of a star’s life is when it is first born, which is called a Nebula; cloud of gas and dust. The second one is a protostar that contracts more dust and gas. The third stage is called young star, that’s when the cloud of gas begins to take life.
The fourth and final stage of a star’s life is called a red giant star, that’s when it loses hydrogen and starts to become cooler, and begin to turn into a white dwarf. It becomes a dying star that is cooling off, and can turn into a black dwarf making it the last stage of a star’s life. However, at the end of its nuclear burning stages, some stars eject most of its outer material, only the hot core of the stars will remain. This core will become very hot which will cool down over the course of the next billion years or so.
In conclusion; where a star ends up at the end of its life depends on the mass it was born with. Stars that have a lot of mass may end their lives as black holes or neutron stars. A low or medium mass star will become a white dwarf. References: http://www. universetoday. com/guide-to-space/stars/white-dwarf-stars http://science. nationalgeographic. com/science/space/universe/white-dwarfs- article. html http://www. tynic. org/2006/NYCO63368/the stars. htm http://imagine. gsfc. nasa. gov/docs/science/know_11/swarfs. html