Due articoli sull’osservazione di quella che potrebbe essere una supernova a instabilità di coppia.
The observations and analysis show that SN2016iet began as an incredibly massive star 200 times the mass of Earth’s Sun that mysteriously formed in isolation roughly 54,000 light years from the center of its host dwarf galaxy. The star lost about 85 percent of its mass during a short life of only a few million years, all the way up to its final explosion and demise. The collision of the explosion-debris with the material shed in the final decade before explosion led to SN2016iet’s unusual appearance, providing scientists with the first strong case of a pair-instability supernova.
https://www.cfa.harvard.edu/news/2019-19
SN 2016iet has a multitude of oddities, including its incredibly long duration, large energy, unusual chemical fingerprints, and environment poor in heavier elements — for which no obvious analogues exist in the astronomical literature. […]
“The idea of pair-instability supernovae has been around for decades,” said Berger. “But finally having the first observational example that puts a dying star in the right regime of mass, with the right behavior, and in a metal-poor dwarf galaxy is an incredible step forward.”