Can anybody explain why there are so many worlds that are incapable of supporting life? IS Jesus also partial to gas giants and red dwarfs. Most stars are currently classified using the letters O, B, A, F, G, K, and M (usually memorized by astrophysicists as "Oh, be a fine girl/guy, kiss me"), where O stars are the hottest and the letter sequence indicates successively cooler stars up to the coolest M class of the 27 closest stars 17 are M type quite invisible to the naked eye. 5 are K type, still smaller than the sun. 2 are white dwarfs, stellar embers of spent stars. one is A type one is a F type, and one is a G type star similar to the sun. Of the hundreds of exo-planets discovered, almost all of gas giants of around Jupiter mass.