2023-08-30 10:33:31
The Pinwheel galaxy, or Messier 101, on May 21, 2023, four days after light from supernova 2023ixf reached Earth. -STEVEN BELLAVIA
MADRID, 30 Ago. (EUROPA PRESS) –
new research on the closest supernova recorded in a decade they are revealing preconditions in stars when they enter an explosive dynamic.
SN 2023ixf, the closest supernova since 2014, recorded just 21 million light years from Earth in the Molinite galaxy on May 18was the subject of the first measurements in polarized light of such an event and showed more clearly the evolving shape of a stellar explosion.
The polarization of light from distant sources such as supernovae provides the best information about the geometry of the light-emitting object, even for events that cannot be spatially resolved.
“Some stars go through ripples before exploding. (an intermittent behavior that gently ejects some material) so that when the supernova explodes, the shock wave or ultraviolet radiation causes the material to glow,” he said. it’s a statement Alex Filippenko, a professor of astronomy at the University of California, Berkeley, co-discoverer of the supernova and author of a new study on the event. “The good thing about spectropolarimetry is that we get some indication of the shape and extent of the circumstellar material.”
The spectropolarimetry data told a story in line with current scenarios for recent years of a red supergiant star 10 to 20 times more massive than our sun: the energy from the explosion illuminated the gas clouds that the star spewed out over the previous years; The ejected material then passed through this gas, initially perpendicular to most of the circumstellar material; and finally, the ejecta engulfed the surrounding gas and evolved into a rapidly expanding but symmetrical cloud of debris.
The explosion, a type II supernova resulting from the collapse of the iron core of a massive star, presumably left behind a dense neutron star or black hole. These supernovae are used as gauge candles to measure distances to distant galaxies and map the cosmos.
Another group of astronomers led by Ryan Chornock and Rafaella Margutti, professors of astronomy at UC Berkeley, collected spectroscopic data. They analyzed the data to piece together the star’s pre- and post-explosion history, finding evidence that it had spewed gas over the previous three to six years before collapsing and exploding. The amount of gas given off or expelled before the explosion could have been 5% of its total mass, enough to create a dense cloud of material through which the ejected supernova had to traverse.
“I think this supernova will make us think in much more detail about the subtleties of the entire population of red supergiants losing a lot of material before the explosion and will challenge our assumptions about mass loss,” said the graduate student and team member. by Chornock Wynn Jacobson-Galan. “This was a perfect lab to further understand the geometry of these explosions and the geometry of mass loss, something we already felt ignorant of.”
A better understanding of how Type II supernovae evolve could help refine their use as distance measures in the expanding universe, said Berkeley graduate student and supernova co-discoverer Segiy Vasylyev.
The two articles describing these observations have been accepted for publication in The Astrophysical Journal Letters. Margutti and Chornock are co-authors of both articles, which are currently available on the arXiv preprint server.
In the more than three months since the light from the supernova reached Earth, perhaps three dozen papers have been submitted or published about it, with more to come as the light from the explosion continues to pour in and observations are analysed. from a variety of telescopes.
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