@dauphin87

here's a nicer image of Pleiades from NASA

@POOetryma

@peeppeepcircus @dauphin87 The Pleiades cluster is what's called an O-B association, named for the types of stars it contains. Stars of spectral classes O & B are bigger, hotter, and brighter than our sun, ranging from 3x the sun's mass to 50x or more and up to hundreds of thousands of times brighter. Some of the B class stars and all of the O class will eventually explode as supernovae in a few million years (must be at least 8 solar masses for this).

@peeppeepcircus @dauphin87 Stars are classified according, mainly, to their mass and brightness. From smallest and dimmest to biggest & brightest: M, K, G, F, A, B, O.

The M stars are small, as little as 8% the sun's mass (0.08 SM) up to about half, and are very cool, dim and reddish. The smallest ones are not much bigger than Jupiter, but are at least 80x its mass, the minimum necessary to ignite and sustain hydrogen fusion in the core. They're only a few thousandths as bright as our sun.

@peeppeepcircus @dauphin87 Next up are the K class dwarves. They're a little bigger and brighter, ranging from around half to almost 90% as big as the sun and about half to 90% as bright. They're a little cooler and tend to shine a more orange color.

Next are the G class dwarves, like our sun. They range from roughly 90% to about half again the sun's mass, and from about 90% to a few times brighter.

There are no M or K dwarves visible to your eyes from Earth and only a...

@peeppeepcircus @dauphin87 ... few G class dwarves you can see, but those have to be rather close by.

Then comes the A stars, which are a couple times more massive and a few dozen to a few hundred times brighter. Sirius is a good example: twice the sun's mass and 25x as bright.

Then come the B stars, from 3 to about 10 times our sun's mass and a few hundred to a few thousand times brighter.

Last are the brilliant blue O stars, up to a couple million times brighter.

^ this is a beautiful image of Pleiades from NASA, then my pic is at the top of the thread @EnochianEntropy