The Lives of Stars. By: Brett Mele, Tyler Knight, Philip Gonyea Dependra How is a star “born”? All star start their lives as a dense part of a nebula. (A big cloud of gas and dust spread out in space.) in the dense part of the nebula the gas and dust becomes so dense and hot that a star is born. Nebulas This is a nebulae. All stars form out of this. They start a protostars, then form into a star from nuclear fusion. Here are some pictures. As you can see this nebula has stars forming around it. What happens to a star when it runs out of fuel? When a star begins to run out of fuel its core shrinks and the outer portion of the star expands. Depending on the stars mass the star either becomes a red giant or a super giant. Red giants, and super giants evolve in many different ways. After a star completely runs out of fuel it becomes either a white dwarf, a neutron star, or a black hawk. This is a picture of a white dwarf. This is a picture of a red giant. This is a photo of a star going nova. Here we have a picture of a star going supernova. This is a picture of a globular cluster. What determines how long a star will live? The mass of a star will tell you how long it will live. You may think that if a star is bigger it lasts longer. But you are wrong. Its kind of like a car the smaller it is the longer it lasts. If the star is very small it will live for about 200billion years. If it is a medium size (like the sun) it will only last about 10 billion years. Scientists approximate the sun’s age to be about 4.6 billion years old. So it is almost half way through its life. And large stars only live for about 10 million years. Star sizes These are some of the sizes of stars. This is a large star. Now here is a quick video showing you the life of a star.