The vast universe that holds such mesmerizing beauty gives the mind something to contemplate as we look up at the night sky. Do you have a favorite star that you love to look at? Do you ever wonder how that special star came to be? Our amazing universe holds the elements that make up our very existence through the birth and death of stars.
Out in the deep reaches of our galaxy, huge molecular clouds of dust and gas swirl around in the dark. If one of these molecular clouds is massive enough, its own gravity will cause it to start to collapse onto itself, becoming denser and hotter. The particles of gas and dust are then brought together and start to fuse into a new born star. As this happens, hydrogen atoms fuse together to make helium. This process is called nuclear fusion and is needed to create every star. Let’s say our new born star is a highly luminous blue star with 10 times the mass of the sun. This high mass star has more gravitational energy making it much hotter than a low mass star. Because our star is higher in mass, it burns through its energy much faster and it will live a much shorter life than a lower mass star like the Sun. When the fusion of hydrogen into helium stops and the hydrogen fuel runs out, the core of the star contracts and the death of the star starts. The transformation process begins again as our once blue star phases into a red giant, an extremely large and bright star. The now red giant will fuse helium into carbon. The core is hot enough to fuse carbon into oxygen and from oxygen to silicon and from silicon to iron. This is the end for fusion because nuclear reactions involving iron do not release energy. Iron builds up in the core. With no fusion to hold up outer layers of core it suddenly collapses. The core implodes within 0.1 seconds at 70,000 km/s, as this happens the temperature rises to 100 billion degrees, one of the hottest temperatures in the universe! Extreme temperatures like this allow heavier elements than iron to form. Electrons combine with protons, making neutrons and the neutrons collapse at the center, forming a neutron star. The in falling material rebounds off the core and causes a shock wave that propagates to outer layers, then the star blows apart, creating a supernova explosion! The shockwave from this supernova takes these heavier elements like Carbon and Oxygen that we are made of to regions of the galaxy where new stars are forming, thus completing the cycle of stellar life and death.
I hope the next time you look at your favorite star, you will have a better understanding of how it came to be and that we all once came from a star.
You’ve been listening to Western Slope Skies, produced by the Black Canyon Astronomical Society and KVNF Community Radio. This feature was written and recorded by Gina Murillo, an astronomy student of Dr. Catherine Whiting at Colorado Mesa University.
