Serena raised her hand. "According to the Spectral Classification, O type stars are the hottest, and the M type are the coolest."


O - Brightest and live the shortest
B - Blue white burn bright, but not as bright as the O type
A - Less bright, a little larger than our Sun, but still burn hotter
F - Brighter than our Sun and a little hotter
G - Our Sun is a G type star
K - Dimmer than our Sun and burns longer because temperature is lower
M - Dimmest stars burn for a long time