Two teams of astronomers have made a compelling case in the 33-year-old mystery surrounding Supernova 1987A. Based on observations of the large Atacama Millimeter Array / submillimeter (ALMA) and a subsequent theoretical study, scientists provide a new insight into the argument that a neutron star is hiding deep inside the remnants of the exploding star. This would be the newest neutron star known to date.
Ever since astronomers witnessed one of the brightest explosions of a star in the night sky, creating the Supernova 1987A (SN 1987A), they have been searching for a compact object that should have formed in the remainder of the explosion.
Because particles known as neutrinos were discovered on Earth on the day of the explosion (February 23, 1987), astronomers expected a neutron star to have formed at the star’s collapsing center. But when scientists could not find any evidence for that star, they began to wonder if it then crashed into a black hole in the ground. For decades, the scientific community has eagerly awaited a signal from this object hiding behind a very thick cloud of dust.
Recently, observations from the ALMA radio telescope provided the first indication of the missing neutron star after the explosion. Extremely high-resolution images revealed a hot “rocket” in the dusty core of SN 1987A, which is brighter than its surroundings and matches the suspected location of the neutron star.
“We were very surprised to see this warm grief made by a thick cloud of dust in the supernova remnant,” said Mikako Matsuura of Cardiff University and a member of the team that found the ball with ALMA. “There must be something in the cloud that has ignited the dust and made it shine. That is why we suggested that there be a neutron star hidden inside the clouds of dust.”
Although Matsuura and her team were enthusiastic about the result, they thought about the brilliance of the point. “We thought the neutron star might be too bright to exist, but then Dany Page and his team published a study that showed that the neutron star can really be this bright because it is so bright. ri, “said Matsuura.
Dany Page is an astrophysicist at the National Autonomous University of Mexico who has studied SN 1987A since its inception. “I was in the middle of my doctorate when the supernova happened,” he said, “it was one of the biggest events in my life that made me change the course of my career to try to solve this mystery. It was like a lattice of modern sacred. “
Theoretical study by Page and his team, published today in Astrophysical Magazine, strongly supports the suggestion made by the ALMA team that a neutron star is amplifying the point of dust. “Despite the supreme complexity of a supernova explosion and the extreme conditions that reign inside a neutron star, the discovery of a warm dust cloud is a confirmation of some predictions,” Page explained.
These predictions were the location and temperature of the neutron star. According to computer models of the supernova, the explosion “hit” the neutron star from its birthplace at a speed of hundreds of kilometers per second (tens of times faster than the fastest rocket). The block is exactly where astronomers think the neutron star would be today. And the temperature of the neutron star, which was predicted to be around 5 million degrees Celsius, provides enough energy to explain the brightness of the point.
Not a pulsar or a black hole
Contrary to popular belief, the neutron star is likely not to be pulsating. “The power of a pulsar depends on how fast it rotates and on the strength of its magnetic field, both of which would have to have very well-regulated values to respond to observations,” Page said, “while the thermal energy emitted by the hot surface of the young neutron star naturally fits the data “.
“The neutron star behaves exactly as we expected,” added James Lattimer of Stony Brook University in New York, and a member of Page’s research team. Lattimer also closely followed SN 1987A, having published before SN 1987A predictions of a neutrino signal of a supernova that subsequently matched observations. “Those neutrinos suggested that a black hole never formed, and moreover it seems difficult for a black hole to explain the observed brightness of the point. We compared all the possibilities and came to the conclusion that a hot neutron star is the most likely explanation. “
This neutron star is a 25 km wide, extremely hot ball with ultra dense matter. A teaspoon of its material would weigh more than all the buildings within New York City combined. Because he could only be 33 years old, he would be the youngest neutron star ever found. The second youngest neutron star we know of is located in the remnant of the supernova Cassiopeia A and is 330 years old.
Just a direct view of the neutron star would provide clear evidence that it exists, but for that astronomers may have to wait several more decades until the dust and gas in the supernova remnant become more transparent.
Detailed ALMA images
Although many telescopes have made images of the SN 1987A, none of them have been able to observe its core with such precision as ALMA. Early (3-D) observations with ALMA already showed the types of molecules found in the supernova residue and confirmed that it produced massive amounts of dust.
“This discovery builds on years of ALMA observations, showing the core of the supernova in more and more detail thanks to continuous improvements in telescope and data processing,” said Remy Indebetouw of the National Radio Astronomy Observatory and the University of Virginia. who has been part of the ALMA imaging team.
Scientists find evidence of missing neutron star
Dany Page et al, NS 1987A to SN 1987A, Astrophysical Magazine (2020). DOI: 10.3847 / 1538-4357 / ab93c2
Provided by the National Radio Astronomy Observatory
citation: ALMA finds possible neutron star sign in supernova 1987A (2020, July 30) taken July 30, 2020 by https://phys.org/news/2020-07-alma-neutron-star-supernova-1987a.html
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