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This animation shows how the massive star Eta Carinae survived a major eruption in the 1840s. In this scenario, Eta Carinae initially began as a triple-star system. Two hefty stars in the system are orbiting closely and a third companion is orbiting much farther away. When the most massive of the close binary stars nears the end of its life, it begins to expand and dumps most of its material onto its sibling. The sibling bulks up and becomes extremely bright. The donor star, having lost most of its mass, moves farther away from its monster sibling and interacts with the outermost star. The two stars trade places, with the outermost star getting kicked inward. The inward-moving star falls into the monster sibling, and the two stars merge. The merger produces an explosive event that forms bipolar lobes of material ejected from the giant star. The surviving companion star settles into an elongated orbit around the merged pair, passing through the monster star’s outer gaseous envelope every 5.5 years.
