Have you ever looked up into the night sky and wondered: What has that star been through? And where will it end up?

Well, then today is your lucky day!
Because I'm going to teach YOU:


THE LIFE OF A STAR


Into the Nebula

Before a star is even a baby, it must start in what is casually known as a stellar nursery (nebulae or molecular cloud complexes). Nebulae are full of hydrogen and dusts! Those bits of iron and other dusts will attract each other through the force known as gravity and form a sort of "core" as hydrogen is pulled around it. More and more hydrogen and dust is pulled, until the mass becomes a proto-star (AKA T-Tauri Star). At this point the proto-star is erractic and creates very strong solar winds (caused by the magnetic field). The surface temperature can reach up to 7000°K! That's over 6 times the heat of some of the hottest lava records!!!



Becoming a STAR!

This is the fun part.
The star at this point is extremely unstable; it's spinning way too fast. So, in a massive burst of energy, matter is expelled from the star (known as Herbig-Haro Objects) thus slowing its spin. This slowing of the stars momentum allows it to collapse into what is known as a main-sequence star.




Life as a Main Sequence Star

Main-sequence stars, such as our sun, are in the prime of their life. But what does main-sequence mean? All it means if a star is called a main-sequence star is that it is fusing hydrogen into helium. This process is known as hydrogen fusion, nuclear fusion, or the proton-proton chain (much larger stars go through the CNO cycle). Happily these stars fuse away their hydrogen. But what happens when they run out?

Sun-like

Stars that are medium-sized will contract and then expand as helium builds up in the core and become a red giant. The core gets so hot and dense that helium is now fused into carbon! Then, the helium flash occurs. It's a huge burst of energy in a short period of time that is absolutely astounding. Now, the giant is fusing hydrogen into helium in the shell around the core and fusing helium into carbon in the inner core. After a long time of fusing, the layers of the star are blasted away, making a sort of large shell around the star sytem. After time, this becomes a planetary nebula.




The Big Boys

Larger stars have a completely different timeline after they leave the main-sequence group. But just like sun-like stars, they begin to fuse helium into carbon. As the star gets more and more massive, eventually it becomes a red supergiant and some fuse elements like neon and oxygen. After some time, the massive giant begins to fuse elements into iron, and that's when things begin to stop. Because iron would take energy to fuse, rather than pushing outwards like the other fusions, gravity takes over and the poor star begins to collapse. But the core pushes back as the outer layers are sinking and the star bursts into what most known as a type 2 supernova. If the star is large enough, a BLACK HOLE will form! If not, an extremely dense mass called a neutron star will form. Neutron stars are the most dense objects in the universe besides black holes. 




Fun Fact: Every galaxy has a black hole in its galactic nuclei (center). Even the Milky Way!



**Not every star will go through one of these processes, such as binary (or more) stars which make up 80% of star systems in the Milky Way. Binary stars are affected by their partner, so interesting things happen in their life cycle**


Thank you for reading!

I hope you learned something!