 Surface gravities are around 10,000 times that of the Earth, relatively low for a main sequence star.Absolute magnitudes range from about −4, 3,400 times brighter than the sun, to about −5.8, 18,000 times brighter than the sun.Class O stars are very young, no more than a few million years old, and in our galaxy they all have high metallicities, around twice that of the sun.