I found an article at, http://www.space.com/22471-red-giant-stars.html . It talks about how the red giant star is a star that is dying. It reaches a size of 100 million to 1 billion kilometers, which is 100 to 1,000 times the size of today’s sun. It’s because the energy is spread across larger areas. The surface temperature reach up to 2,200 to 3,200 degrees Celsius. Stars spend approximately 3,000 to 1 billion years as a red giant. The star shrinks until a new helium shell reaches the core.
When the helium ignites, outer layers are blown off in huge clouds filled with gas and dust which is called planetary nebulae. The core collapses on itself and the smaller stars such as the sun end their lives as white dwarfs. The sun will begin the helium-burning process which takes place in around 5 billion years.
After it expands, its outer layers will consume the planets, including Earth. When stars turn into red giants, it can actually become habitable for other planets. Habitable zones is a region that water can exist in. A red giant can exist for a billion years which is a possibility that life can form. My personal opinion of this article is overall good because it has a lot of interesting facts. I would recommend people to read it. This article connects to what I have learned in class because it talks about the stars lifetimes and energy production which is what we went over in class. I learned in class that most energy released by fusion starts its journey out of the solar core in the form of protons. The clicker questions also helped out.