The stars are projectors. Well, at least according to Modest Mouse.
Humans have a pretty interesting relationship with the starlight that emits from the night sky.We make wishes upon stars. We sometimes even say that our fate is written in them. Stars have acted as a muse for countless artists, from Vincent Van Gogh to Walt Whitman.
I decided to write this very article under the night sky. Trust me, it’s way less romantic than it sounds. I’m just an insomniac with a MacBook. Still, our fascination with the balls of gas that gleam and glitter in the night is undeniable.
So, what are the different types of stars? From your backyard, they may look more or less identical, some shining slightly brighter than others. You’re lucky to see them at all, apparently, thanks to rampant light pollution.
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Before we jump in all starry-eyed, we want to note that there are several different ways to classify stars. From noting spectral types and chemical composition, to luminosity classes and temperature, astronomers have a pretty complex organizational system in place to categorize those bright balls in the night sky that we make wishes on.
The work of American astronomer/badass Annie Cannon was especially crucial to the development of OBAFGKM, a kind of mnemonic astronomers use to remember spectral type letters. OBAFGKM is most often referred to as “Oh! Be A Fine Girl/Guy – Kiss Me!”. I know I said that writing this article under the stars wasn’t romantic, but wow, things are definitely heating up.
Okay, onto the main event. Let’s go stargazing.
The prefix to this little wonder gives away much of its meaning.
The word “proto-” means first or original, and is aptly used to describe this star. Just as human beings begin to grow from a stage of infancy, stars begin their celestial journey as protostars.
The stellar nursery, aka the molecular clouds where stars form, is where these baby stars can be found. Just how long do protostars stay cosmic newborns? A cool 100, 000 years.
Observed to be born in clusters, prepubescent stars are quite social. When it comes to looking at the life cycle of stars, Protostars are considered to be the beginning of things, so it only makes sense that they’re our first stop on our stellar sightseeing tour.
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2. Main Sequence Star
A whopping 90% of all stars in the universe fall under this category of star, so the next time you make a wish under the night sky, it’s probably on one of these.
Just because they’re common doesn’t mean they are uninteresting.
They can range from a tenth the size of the sun to nearly 200 times as large! Yes, even our own sun is a main sequence star (specifically, a yellow dwarf). This category of the stellar life-cycle also includes the Red Dwarf Star, which you can read about in the very next section. Convenient, I know.
3. Red Dwarf Star
Half as massive as the sun, a Red Dwarf can last 80 to 100 billion years. It is cool, very faint, and small. Amongst all main sequence stars, the red dwarf is the most common in the milky way, but due to luminosity, they’re actually pretty difficult to see.
Long-living and too dim for the naked eye to observe from Earth, the Red Dwarf is 7.5 to 50 percent the mass of the sun.
4. White Dwarf Star
These ancient stars are also referred to as a degenerate dwarf star (ouch).
Stars with low to medium mass, less than 8 times the mass of the sun, eventually become these degenerate stars.
White Dwarfs are incredibly dense stars who fuse hydrogen within their cores into helium in order to survive. They’re essentially just burned-out cores of collapsed stars.
Think of them as the solar system’s aging stars, the evolutionary endpoint to an awesome cosmic journey.
5. T Tauri Star
In stellar terms, the T Tauri Star is a cosmic toddler.
100, 000 to 10 million years old, they rest over 400 light years away and are characterized by erratic changes in brightness. These pre-main sequence stars can have intense stellar winds and are in the process of gravitational contraction.
They weigh under 3 solar masses. Not a protostar, not yet a main sequence star, T Tauri Stars are actually considered to be a kind of pre-main sequence star.
6. Supergiant Stars
As the name implies, these are truly enormous stars. In fact, they’re the largest in the universe.
They make the sun look puny in comparison. They can be thousands of times larger and have a much larger mass than our own sun. Enormous and incredibly hot, when they reach the end of their life they explode into a supernova, which produces either a black hole or a neutron star.
Anyone else think of this song when they read the word supernova?
7. Neutron Stars
Okay, so thanks to the last entry, we know that when giant stars die, they form one of these.
A Neutron star is essentially a collapsed core of a large star, the consequence of supernova explosion and gravitational collapse.
Don’t get them mixed up with a black hole, though. They’re slightly different. If a Neutron star was denser, it would collapse into a black hole.
This may sound pretty morbid, but… isn’t stellar death just incredible?
Galaxy Monitor thinks so.
Our stargazing date has come to a close.
How well can you see the stars from your own backyard? What phrase other than “Oh Be A Fine Guy/Girl, Kiss Me” can you think of to remember the spectral type acronym OBAFGKM?
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