Although huge stars often die in spectacular explosions, some explode like nasty fireworks. Astronomers identified the remnants of one such nasty firework at SGR 0755-2933, neutron star about 11,400 light-years away Soil in the southern constellation Lyalka. In a new study, scientists find that early in life star transferred an abnormally large amount of mass to its twin friend – so much so that there was not enough material left for an explosive death. Instead, it was a quiet “ultra-split”. supernovaA rare cosmic event that left behind an ultra-dense remnant called a neutron star.

“This amazing binary system is essentially a 10 billionth system,” he said in a statement. Andre-Nicolas Chanet, an astronomer at the National Science Foundation’s NOIRLab research center and co-author of the new study.

A neutron star and its close-orbiting binary companion—a star that researchers predict will one day collapse to become a neutron star—are the first clear examples of a star system that will eventually result. Kilonova — a cosmic explosion that would reveal two neutron stars. merger

Despite being a kilonova first discovered in 2017 The following year, astronomers recorded only the results of the event, thanks to their observations of light and gravitational waves. The new study is the first time scientists have identified a binary star system that they knew would result in a Kilonova explosion.

In addition, astronomers have previously observed spiral galaxies like ours. Milky Way, there will be only one or two such systems. The researchers of the latest study increased this score to 10, noting that these observations help them better understand the history, evolution and unusually silent death of stars in such systems.

“For some time, astronomers have speculated about the exact conditions that could eventually lead to a kilonova,” Chenet said in a statement. Said. “These new results suggest that, at least in some cases, two sister neutron stars can merge when one is formed without a classical supernova explosion.”

The sister star is very massive, orbiting the main neutron star every 60 days, and has a name similar to its plate: CPD-29 2176. The scientists behind the latest study studied the sister star to understand the formation of the current star system and how it came to be. may occur in the future.

“This is not a simple binary system”

Clarissa Pavao, a student at Embry-Riddle Aeronautical University in Arizona, found the system while analyzing data collected by the Cerro Tololo Inter-American Observatory in Chile. He specifically built spectrum sister stars, analysis of how much light a star emits at certain wavelengths. After clearing the data of the noise, he noticed a simple line in the spectrum indicating that the massive star had a circular orbit, an unusual feature in binary star systems.

To the astronomers, this was an important discovery that helped the team conclude that the primordial neutron star ended up as a supernova.

Usually when a star in a binary system burns its hydrogen and nears the end of its phase home directorybegins to transfer mass to its companion star. As a result of the end-of-life explosion, satellite stars are often ejected from systems into highly elliptical orbits.

However, this does not seem to have happened in the intriguing system. To better understand what might have happened at the end of SGR 0755-2933’s life, astronomers have studied thousands of models describing binary star systems as they studied. They found only two that matched.

The team then traced the star’s history and concluded that it behaved like any other massive star that ran out of fuel: At the end of its life, the star began transferring mass to its companion and turned into a low-mass star. with a helium core, as scientists expected. However, the star lost so much mass in the process that its end-of-life supernova “didn’t even have enough energy to push the orbit into the more typical elliptical shape seen in such binary systems,” he said. He is an astronomer at Embry-Riddle and lead author of the new study. The dying star also didn’t have enough energy to kick its companion out of the system, so the two stars’ orbits continue to be narrow, according to the study.

Determination of the beginnings of precious heavy metals

In addition to learning more about kilonova events, the new research will help astronomers better understand the origins of some of the heaviest elements in our universe.

A silent supernova occurred only a few million years ago, and astronomers expect the CPD-29 2176 system to remain so for at least another million years. Their model shows that like the primary neutron star, the sister star will also transform into an ultranova supernova and eventually into a neutron star.

The team predicts that millions of years later, the two neutron stars will slowly spin toward each other in a cosmic dance, eventually colliding in a Kilonova explosion. Explosions like this have been known to happen. source Large quantities of heavy elements such as platinum, xenon, uranium and gold were “ejected into the universe”, Richardson said.

Astronomers have long suspected that heavy metals released during such events floated in the interstellar medium to form asteroids and then bombarded Earth, accumulating the precious metals we see today. Only the 2017 Kilonova event resulted in a launch valuable carries heavy metals to Earth by at least 100 units, so a failed supernova doesn’t seem like that big of a loss for the universe.