The Final Act
AG Carinae is one of the most luminous objects in the Milky Way, a once massive O type star it has begun it's final act, moving from a stable main sequence star to a Wolf Rayet star, an unpredictable, unstable giant star.
So what's going on ? As the star begins to run out of fusible material, the fusion pressure pushing outwards begins to temporarily lose the battle with gravity, the star momentarily begins to collapse, crushing down on the star which then puts more fusion pressure on the star, and counter acting the gravitational collapse. The counter action causes the outer layers of the star to explosively push outwards, losing a huge amount of mass in these periodic outbursts.
Unlike stars like our Sun, the loss of a hydrogen outer layer means these Wolf Rayet star will never move to a red giant phase (where the outer layers of hydrogen stabilises the helium fusion core), instead, the star will continue to become more and more unstable, reaching the full status of Wolf Rayet.
Eventually, a final outburst will reduce the stars fusible material to such a point, it will collapse and a supernova will occur with a high likelihood of creating a black hole.
