☆Born to shine, forced to fuse☆

Stars, like us, have an exciting life journey. Stars are born when gas and dust in cold molecular clouds collapse from gravity. Just like our solar system, the formation of a star involves the gas cloud spinning, heating, and flattening until the star is formed. Something I thought was cool was that stars tend to form in groups!! These star-forming molecular clouds don’t just pop out one star at a time, but rather many.

But what determines which path the star will go down in its life? The most important characteristic of a star is its mass, because from that we can learn about its temperature, luminosity, and life journey. Depending on how massive the star is, their lives can be vastly different.

For low-mass stars, such as our Sun (crazy, right? our Sun is one of the smaller ones!), they live a slow and steady life of generating light to shine by fusing hydrogen atoms to helium. But when they run out of hydrogen to fuse, the star isn’t strong enough to resist gravity, and it will start shrinking. This is when the star transitions into a red giant, which is much larger and more luminous! In this stage, the star will fuse helium atoms until it runs out, and then the star will finally collapse. It will become bigger and more luminous as before, but eventually it will scatter into a beautiful planetary nebula.

Star ashes!! (Image credit: NASA, ESA and the Hubble Heritage)

High-mass stars have a similar childhood to low-mass stars in that they convert hydrogen and then helium to get energy, but they do that much faster and are able to fuse heavier elements. This is because these high-mass stars have much higher temperatures that allow them to fuse heavier nuclei! That is, until we get to iron. The star will then run out of energy and start dying. When a high-mass star dies, it explodes into a supernova!! It might leave behind a neutron star (a very massive ball of neutrons) or even a black hole!

The death of stars is what allows more stars to be born. The material that a star produces during its lifetime will be able to birth new stars and planets! And the elements that were created from high-mass stars are what we are made of! So if you learn anything from this blog, remember that you are made of star stuff. ☆