Astronomers were finally able, after 37 years, to solve a “cosmic murder mystery” after they discovered a neutron star in the debris of a stellar explosion.
Scientists indicated that they have found evidence that reveals the mystery of what happened in the aftermath of the most famous stellar explosion, called 1987A, which is the presence of a neutrino star that remained hidden by debris for 37 years.
Supernova 1987A represents the remains of an exploded star that once had a mass of about 8 to 10 times the mass of the Sun. It is located about 170,000 light-years away in the Large Magellanic Cloud, a dwarf galaxy adjacent to the Milky Way.
Supernova 1987A was first observed by astronomers 37 years ago in 1987, hence its name.
As it exploded, Supernova 1987A first showered Earth with ghostly particles called neutrinos and then became visible in bright light. This made it the closest and brightest supernova seen in the night sky above Earth in about 400 years.
Supernovas are known to result from the collapse of stars with a mass between eight and ten times the mass of our Sun.
Supernova explosions like these are responsible for feeding the universe with elements such as carbon, oxygen, silicon and iron. These elements eventually become the building blocks for the next generation of stars and planets, and can also form molecules that may one day become an integral part of life as we know it.
These explosions also generate compact stellar remnants, either in the form of neutron stars or black holes, and for 37 years, astronomers did not know whether 1987A left an ultra-dense neutron star or a black hole.
Astronomers have searched for evidence of any of these compact objects at the center of the expanding remnant ever since.
Scientists have long suspected that the 1987A explosion left behind a neutron star, but there was so much dust left behind that even the most powerful telescopes could not confirm it.
But now, a team of scientists say they have found the first evidence of a neutron star lurking within the debris.
Dr Maggie Adrien-Pocock, presenter of BBC Sky at Night, said the research team had "solved a cosmic murder mystery. It's about the death of a star and the mystery is what lies in the shrouds of dust around what's left."
Using two instruments aboard the James Webb Space Telescope (JWST), scientists looked at infrared wavelengths of light coming from the supernova region and found heavy atoms of argon and sulfur that had been stripped of their outermost electrons.
By modeling how these atoms got there, scientists found that they could only have been formed by a neutron star.
“Our data can only be fed by a neutron star as the energy source for this ionizing radiation,” explained Professor Mike Barlow, an astronomer at the University of California and co-author of the study.
Scientists have two theories about how this happens.
Professor Barlow explained: “This radiation could be emitted from the surface of the hot million-degree neutron star, as well as from the pulsar wind nebula that would have been created if the neutron star was rotating rapidly and pulling charged particles around it.”
When neutron stars collapse, they heat up to billions of degrees on the surface.
When it cools, this energy is released into the universe in the form of huge amounts of ultraviolet radiation and X-rays.
But if the neutron star were rotating, it would actually pull a "wind" of relativistic particles around itself that could interact with the surrounding supernova material.
An example of this kind of force can be seen in the Crab Nebula, a supernova remnant observed by Chinese astronomers in the year 1054.
Either way, scientists now have a strong indication that a neutron star exists.
Professor Barlow added: “The mystery of whether a neutron star is hiding in the dust has persisted for more than 30 years, and it is exciting that we have been able to solve it.”
The asteroid Dimorph was deformed after colliding with the DART probe
The DART probe collided with the asteroid Dimorph in September 2022, and scientists are studying images taken by the cameras of the small satellite LICIACube in the first minutes after the collision.
Nature Astronomy magazine indicates that it became clear to scientists from their study of the images that the collision changed the orbit of the asteroid and caused a major distortion in its body.
The scientists’ report stated: “Our analysis of the data and images showed that Dimorph is not a homogeneous celestial body, but rather a mass of debris that was subjected to significant deformation after colliding with the DART probe. This indicates that the European Hera probe mission, which will be launched this year to Dimorph and Didyma, will not take pictures.” "The crater on the surface of the asteroid, but also new images of its completely renewed surface."
These conclusions were reached by a group of astronomers at the University of Bern in Switzerland, headed by Sabina Raducan, after comparing images taken by the small satellite LICIACube before and immediately after the collision.
The results of calculations conducted by scientists showed that Dimorph is a non-dense agglomeration of debris and that about 35 percent of it is voids. Therefore, the collision of the DART probe with the surface of the asteroid did not lead to the formation of an impact crater on its surface, but rather to restore its structure and shape and renew its entire surface. According to them, this should be taken into account when studying the new Dimorph images that will be taken by the Hera probe, which is scheduled to be launched in October 2024.
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