O-type main sequence star

Properties

Their light-driven stellar winds have a terminal velocity around 2,000 km/s. The most luminous class O stars have mass loss rates of more than a millionth M_☉ each year, although the least luminous lose far less. O-type main sequence stars in the Large Magellanic Cloud have lower metallicity (which makes their interiors less opaque than typical stars in the Milky Way) and noticeably higher temperatures, with the most obvious cause being lower mass loss rates, reduced because of their lower opacity.