Star Spectrum Types

Star Spectrum Types are the types of stars based on their surface temperatures. These spectrum types range from O, B, A, F, G, K, M, L, T, and Y with O being the most massive and hottest and Y being the least massive and coldest.

A star type looks like this: K3V The K means the spectrum type The 3 means how low/high the spectrum type is The V means the star's stage, V means main-sequence, and the rest (IV III II I Ia Iab Ib) means giants.

Blue Giants
Blue Giant stars are the most massive stars, they have a spectral class of O or B or sometimes A. THere is also sometimes a W spectral class for Wolf-Rayet stars.

White Stars/Giants
They have a spectral class of A or F. Are white giants.

Yellow Dwarfs
Are stars with around 1 solar masses and are good for life. Sometimes has a lot of planets. The sun is a yellow dwarf with a lot of planets, and yellow dwarfs have spectrum class of G.

Orange Dwarfs
Are stars with around half a solar mass and are the best for life. Most has a lot of planets and has a long lifespan, but sometimes the planets can be tidally locked. Has a spectrum class of K.

Red Dwarfs
Not to be confused with red giants, has around a quarter solar mass and are good for life except the planets are usually tidally locked with the star. making one side permanently daytime and the other side permanent darkness. Has a spectrum class of M and is the most common star type in the universe with 70% of the stars being red dwarfs (not incluing brown dwarfs)

Brown Dwarfs
A red dwarf with just enough mass to start neuclear fusion when it just formed, but then stops due to not enough mass, leaving a gas giant that still has heat which cools down over time. This is called a brown dwarf. First starts off with a spectrum class of L or maybe T, but then cools down to be T and Y spectrum classes.