What is a black dwarf, white dwarf, protostar, neutron star and black hole
I suggest you Google each of these terms.
alright i got all but two.. what is a black and white dwarf star..?
http://www.universetoday.com/41096/black-dwarf/
http://en.wikipedia.org/wiki/White_dwarf
A black dwarf, white dwarf, protostar, neutron star, and black hole are different stages in the life cycle of a star.
1. Black Dwarf: A black dwarf is a hypothetical object that occurs at the end of a star's life cycle. It is formed when a white dwarf, the next stage we'll discuss, cools down and no longer emits light or heat. However, this is purely theoretical, as the universe is currently not old enough for any white dwarfs to have cooled down to become black dwarfs.
2. White Dwarf: A white dwarf is a compact star that forms when a star like our Sun runs out of nuclear fuel. During this stage, the outer layers of the star are expelled, leaving behind a small, dense core made mostly of carbon and oxygen. This core is about the size of Earth but has a mass comparable to the Sun, making it incredibly dense.
3. Protostar: A protostar is the early stage of star formation. It begins when a large cloud of gas and dust, known as a molecular cloud, starts collapsing under its own gravity. As the cloud collapses, it heats up, and a rotating disk of material forms around the central core. Over time, the core becomes denser and hotter, eventually reaching a point where nuclear fusion ignites, and the protostar becomes a main-sequence star.
4. Neutron Star: A neutron star is an extremely dense remnant left behind after a massive star undergoes a supernova explosion. During this process, the outer layers of the star are expelled into space, while the core collapses under gravity. If the core is between about 1.4 to 3 times the mass of the Sun, it becomes a neutron star. Neutron stars are incredibly small but incredibly dense, with a teaspoon of neutron star material weighing millions of tons.
5. Black Hole: A black hole is formed when a massive star's core collapses under gravity during a supernova explosion. If the core is greater than about 3 times the mass of the Sun, it forms a black hole. In a black hole, gravity is so strong that nothing, not even light, can escape. Black holes have a boundary called the event horizon, beyond which nothing can be observed or communicated back to the outside universe.
To understand these astronomical concepts more thoroughly, you can explore resources like books, scientific articles, or educational websites.