What is the life cycle of a star?

Answer 1

Birth; Fear; Rise; Shine; Booze; Drugs; Rehab......Oh I'm sorry I didn't realize this was in Astronomy I thought it was in Lindsey Lohan & Celebs category.

Answer 2

Stellar evolution can become a bit complicated, but I think I can sum it up somewhat easily.

First, the star is born from what is called a molecular cloud. Gravity takes this gas and compresses it, eventually forming it into a ball of plasma, or a star.

Then comes about 90% of a stars life, known as the Main Sequence. During this time, hydrogen at its core is turned into helium through nuclear fusion. The star at this point can be many different sizes, from small to large. Interestingly, larger stars have more hydrogen, but require so much more energy than smaller ones, that they burn thorugh theirs faster, and can only live hundreds of millions of years. Compare that to our Sun's expected life of about ten billion years, and stars smaller than the Sun, red dwarfs, can last tens to hundreds of billions of years.

Then comes the end. The hydrogen in the core runs out and the star can no longer fight against gravity and begins to collapse. But as it gets smaller, the core get hot enough to begin fusing helium into heavier elements like iron, and this added energy is like the stars last gasp of breath. The star expands because of this energy, and becomes huge, what is called a Red Giant. Red Dwarfs, the small stars I mentioned earlier, never do this because they're too small. Red Giants are the most common, but not the only, things that happen as a star dies. Anyway, this added size is mostly gas, I think, and as the star increases in size its gravity can't keep it together and its outer layers fly into space, creating what is called a planetary nebula.

This nebula leaves behind a small core. If this core is smaller than about 1.4 solar masses, the star ends its life as a white dwarf, which is compressed to roughly the size of the Earth. If the core is bigger than this, its now iron core continues to cause fusion until it collapses again, causing an enourmous explosion known as a supernova. What is left behind after this is a smaller core known as a neutron star, because as the star collapsed, it forced protons and electrons together, making them into neutrons. Lastly, the biggest stars become black holes after the supernova.

I know this was long and I apologize, but that's the best way I can explain it. It's pretty complicated stuff.

Answer 3

It depends on the type of star, which is primarily influenced by it's mass. The life cycle, and ultimate fate of stars varies wildly. The Wikipedia entry on 'star' is pretty comprehensive, if a little technically dense at times. Check it out:

http://en.wikipedia.org/wiki/Star

Answer 4

That would depend on the life style the particular star chooses, just realised the category im in sorry haven't a clue, I would imagine it burns in space till it burns no more

Answer 5

Hi. This will explain it. http://library.thinkquest.org/04apr/00533/Astronomy%20Web%20Site/Stars2.htm