S Doradus is one of the brightest stars in the Large Magellanic Cloud, a satellite of the Milky Way. A hypergiant, it is one of the most luminous stars known (sometimes more luminous than −10 absolute magnitude), but so far away that it is invisible to the naked eye.
This star belongs to its own eponymous S Doradus class of variable stars (these classes are usually named after their prototypes); also designated as the class luminous blue variable or LBV, of which S Doradus forms the archetype. S Doradus exhibits long, slow changes in brightness, punctuated by occasional outbursts. Although it has a nominal stellar classification of A0e, in 2000 it was found to have the spectrum of an F-type star (F0).