Life Cycles of Stars

Just like humans, animals and plants stars have life cycles too, the process in which the object develops into different stages. For example, humans have the life cycle of baby, child, teenager, adult and elderly people. For stars, it’s a bit more complicated. Stars have three main sequences: High mass, average mass and low mass. But they all start in the same place: a star nursery. If you look up at the sky at night, locate Orian’s belt (three stars in line) then look to the top right of it you should see a few faint blue dots. That’s the Pleiades (or the Seven Sisters). The Pleiades is a star nursery. It’s where a large star has exploded in what is called a supernova and the mass has collected into little patches that become stars. The little blue dots that you see are the largest of the baby stars (or more accurately, protostars).

First, we are going to understand the life cycle of low mass stars. These stars don’t have that much of a life cycle. It’s just protostar then a red dwarf. A red dwarf is a slow small and relatively cold star. They can live for tens of trillions of years depending on their size (the smaller the longer it will live, due to the bigger the star the more fuel it uses). They are the most common of stars in our universe. About half of the stars are red dwarfs. Red dwarfs do usually have a system of planets around them but they most likely would not have life on them due to how close the goldilocks zone is. This is a problem because the planets would get bombarded with solar storms and wind exposing high radiation to the planets.

Next up is average mass stars. Our star is an average mass star. Their life cycle usually consists of the protostar, main sequence, red giant, white dwarf. The sun is in its main sequence and it is about halfway through its life. It is running out of fuel and is already expanding going into its red giant stage. The red giant does what it says on the tin. It is a massive star and it turns red. Finally, white dwarfs are when the average mass star runs out of fuel and is too heavy and it collapses on itself. As you can probably guess in this stage of the star’s life the star is tiny. Over long periods of time, the white dwarf fades into more of a black or brown dwarf.

Finally comes the high mass stars. The high mass stars life cycle is very similar to the average stars life cycle but just bigger. As they start as protostars (but just bigger ones) then comes the main sequence (just bigger than the average mass stars) next is the red giant (except it’s called a super red giant) but then come the differences. Depending on whether it is a large or not so large high mass star, when it runs out of fuel it either turns into a neutron star or if it is a more massive one, it turns into a black hole. But this all happens after it explodes in what is called a supernova. If you want to see a super red giant, go back to Orion’s belt and look a bit higher then it and to the left and you will see Betelgeuse. Betelgeuse is the ninth brightest star in the night sky with a magnitude of 0.42.

Betelgeuse top left

Anyway, hope you enjoyed today’s blog. Farewell, I will see you in the next one!

Leave a Reply

Your email address will not be published. Required fields are marked *