Eta Carinae's Great Eruption (1837-1858)
Eta Carinae, a massive binary system 7,500 light-years away, underwent a decades-long outburst that briefly made it the second-brightest star in the sky. The star ejected 10-40 solar masses of material but survived, creating the spectacular Homunculus Nebula visible today.
The eruption was initially mistaken for a supernova. The star's survival established 'supernova impostors' as a distinct phenomenon.
Eta Carinae remains unstable and is expected to explode as a true supernova within the next million years. Its eruption demonstrated that massive stars can have violent outbursts short of complete destruction.
Failed supernovae must be distinguished from supernova impostors like Eta Carinae's eruption. The key difference: impostors leave a surviving star, while failed supernovae leave a black hole. Careful long-term monitoring is required to tell them apart.
