WR stars are young stars still burning hydrogen in their cores, rather than evolved stars fusing heavier elements. They show the WR characteristics of strong helium and nitrogen emission because they are strongly convective all the way to the core and have dredged up fusion products to the surface. About two million years ago, WR22 would have been an even hotter O type main sequence star with a mass of around . It will soon exhaust the hydrogen in its core and evolve into a classical hydrogen-poor WR star, possibly after a period as a luminous blue variable then explode as a supernova. The secondary star is expected to have a more traditional evolution into a red supergiant in a few million years time. References Carina Nebula Wolf–Rayet stars Carinae, V429 Carina (constellation) Durchmusterung objects 053208 4188 092740 O-type giants Eclipsing binaries