In 2016, one of the PAN STARRS Observatory telescopes spotted a supernova so bright that it far surpassed its own galaxy, located 3.6 billion light-years from Earth. After more in-depth reviews, made possible by Hubble, the Keck and Gemini observatories (Hawaii), and the MDM and MMT observatories (Arizona), it ultimately turned out that the object, dubbed SN2016aps, was the brightest supernova never seen.
“We can measure supernovae on two scales: the total energy of the explosion and the amount of this energy that is emitted in the form of observable light or radiation,” says Matt Nicholl, lead author of the study published in Nature. Astronomy. “In a typical supernova, radiation represents less than 1% of the total energy. But with SN2016aps, we found that the amount of radiation was five times greater. It’s the biggest light we’ve ever seen emitted by a supernova to date. ”
The researchers also determined that the mass of this supernova was 50 to 100 times that of our sun. For comparison, a typical supernova has a mass generally between 8 and 15 solar masses.
A rare event
Due to its mass and luminosity, Scientists suggest that the star could be a model of “pulsating pair-instability” supernova – an event theorized for decades but never observed.
“To undergo this type of explosion, stars must be born with incredibly large masses: at least 70 times the mass of our sun,” said Edo Berger of Harvard University in the United States. “Basically, there are few stars of this type, but the other ingredient required is that these stars must also be born of gases with low metal content. In other words, gases that have not been enriched by previous stellar generations. “
Then two stars of this type would have to collide, creating a new unstable star in the process. In the idea, this star then undergoes violent pulsations before dying, releasing gigantic gas shells. After an explosion, if the supernova gets the right timing, it can catch one of these shells and release an enormous amount of energy at the time of the collision.
According to the researchers, such an event could therefore explain the brilliance of this supernova. “We think he is one of the most compelling candidates for this process to date, and probably the most massive,” the study said.
Finally, note that while the outer layers expelled by the star offer us a real light show, its core has collapsed into an incredibly dense object. It could be a neutron star or a black hole. But because SN2016aps is so bright, Scientists will have to wait (probably years) for the light to dim enough to finally be able to see what’s behind it.