Why do some stars become 'supernova impostors'? Astronomers still don't quite know

Staring up at the night sky, you might envision a star flaring up, burning thousands of times brighter than usual. That's a cosmic explosion — a supernova! Except it isn't. The star lives on. These violent, non-fatal eruptions can make a star mimic a true supernova — leading to what we affectionately call "supernova impostors." These are massive stars , prone to titanic temper tantrums, blasting out huge amounts of their own material. …