Stellar Evolution Part 2: Main Sequence Stars

When nuclear fusion begins in a star, it joins the main sequence. After billions of years, it will run out of hydrogen to fuse in its core. When this happens to a low-mass star, it will transform into a red giant and, eventually, a planetary nebula. Part 2 of our 3-part series about the life cycles of stars. Learn more at https://astrocampschool.org/stars-part2/ Photo Attributions: http://www.nasa.gov/mission_pages/spitzer/multimedia/pia13275.html http://www.eso.org/public/images/eso0644a/