Astronomers have observed a supernova, unlike any observed so far, and this may be evidence of an important star death that would shape early galaxies.
The supernova, called SN2016iet, does not fit into the classification schemes that scientists use for supernovae today. It looks like the "super volatility of a couple" that would happen among the heaviest stars.
And according to a research team led by Harvard graduate student Sebastian Gomez, this may be the most massive star ever seen under a supernova.
"Finding something so different from everything we know is exciting," Edo Berger, author of the study and professor of astronomy at Harvard University, told Gizmodo .
The Gaia Milk Road Mapping Telescope first spotted the flash on November 1
How is this supernova different? For one, most supernovaes glow once and after a few months fade from the point of view of astronomers. But the SN2016iet brightened and dimmed twice, and its remains are still preserved. His spectral signature contains no evidence of hydrogen or helium, which would ordinarily place him in one of the other supernova categories, but SN2016iet shows an abundance of calcium and oxygen not compared in other supernova observations.
Even the place where it happened is strange, far from the center of a galaxy with unusually low levels of heavier elements.
Three years of observations, along with mathematical modeling, show that once a star could have been 130 to 260 times the mass of the Sun, it would have cast most of its external hydrogen and helium over time, becoming a dense nucleus Of heavier elements left over from synthesis.
If the models are correct, then the gamma rays, which usually create an external pressure in the core, will instead be absorbed by the neutrons of these heavier elements and the star will collapse on itself under the weight of its own gravity. The result would be a nuclear explosion, a process called supernova instability supernovae.
This is the first such candidate for instability of the pair, in which the amount of heavier elements and the initial star's derived mass fit into theoretical predictions, according to an article in The Astrophysical Journal .
It's an exciting subject, but there is definitely more to learn. "The parameters needed for this scenario, in particular the disposal of material very soon before the explosion, are not well explained by current models of this class," says Kate Maguire, an assistant at Trinity College, Dublin, at Gizmodo in email.
"The main limitation of the article is that the theoretical models made so far cannot explain all its properties, and therefore there is no clear result as to what type of star burst and how."
If this Supernova really it was a supernova instability couple, that's exciting, Berger said. "I think these explosions were probably more common in the early universe," among the first generation of massive stars. These supernovae could shape the way the chemical compositions of galaxies look today. SN2016iet could be a local example of something else limited to the farthest universe.
Physicists will use the Hubble Space Telescope to continue exploring this strange object in 2021.