Space is full of surprises, like this apparent star – which, given the anomalous circumstances of its formation, should not really exist.
New research published in Astronomy and Astrophysics describes a possible new kind of star, born in an event that is usually associated with destruction rather than creation: the merger of two white dwarfs. The paper, co-authored by astronomer Lydia Oskinova of the University of Potsdam, combines our understanding of this system, called IRAS 00500 + 6713, which attracted the attention of astronomers in 2019.
Indeed, this strange astronomical case is providing astronomers with “new evidence of possible scenarios where supernova-like explosions arise without completely destroying the object,” said Josa Schwab, a theoretical astrophysicist at UC Santa Cruz , Which are not included in the new study, explained. In an email
White dwarfs are remnants of dense, dead sun-like stars. Pairs of white dwarfs often come together, resulting in a large stellar explosion known as a Type 1A supernova. This was the case for the IRAS 00500 + 6713, but was not strong enough to destroy the detonation system; Instead, it resulted from the creation of an unknown type of astronomical object, new research suggests.
This IRAS 00500 + 6713 was somehow unusually clearly evident to the scientists who originally described the system in 2019. It includes a super hot central star, named J005311, surrounded by a nebula filled with hot gas and hot dust. The star contains a lot of oxygen and carbon, but its strong winds move away from the chart at 10,000 miles per second (16,000 km / s). In an email to Gizmodo, Oskinova stated that no other such object has ever been seen before. In fact, the object, which was observed in infrared, seemed too bright to be white dwarf, prompting new research.
Using the European Space Agency’s XMM-Newton Space Telescope, Oskinova and her colleagues observed that the nebula glows in X-rays and contains a large amount of the element neon.
“Our X-ray observations made it possible to determine the chemical composition of the nebula, and strongly improved our knowledge of the chemical structure of the central star,” explained Oskinova. “We found that there is a lot of neon, silicon and sulfur in the system. In addition, X-ray observations revealed that the nebula is filled with very hot gas at temperatures of a few millions of degrees, and the central star is also a source of X-ray emission. ”
Theoretical modeling suggests that this object is the result of two white dwarfs coming together. The heavy white dwarf pulled the substance from the light companion, eventually triggering a supernova explosion – but one too weak to completely destroy the system. At the same time, however, the explosion was still strong enough to eject critical material. Oskinova and her colleagues believe that the neon-rich nebula is the excretory material, and that a Coisevius object managed to keep the weak supernova alive, allowing it to evolve into the star we see today. At least, according to this scenario.
“IRAS 00500 + 6713 is a newly discovered celestial object. We are not aware of other objects with similar properties. “Oskinova said. “We can call it a very unusual star.”
The team was not able to determine the mass of the object, but its high brightness corresponds to an object heavier than 1.4 solar mass, which is the upper limit for a white dwarf (any heavier and it turns into a neutron star). .
Schwab said that new X-ray data and subsequent analysis improve our knowledge about the chemical composition of the object.
“The results suggest that the oxygen-neon white dwarf and carbon fusion phenomena involved both reinforce the case that this particular object is a large remnant of the merger of the two white dwarfs,” he explained.
Future work said, Schwab, which includes both theoretical modeling and Nebula’s observations, would need to fully understand the nature of the explosion, which produced the unusual star. In fact, apart from a new kind of star, these researchers have stumbled upon a completely new way of supernova explosion.
Interestingly, Oskinova hopes that these objects are quite common in our galaxy. Such stars have probably been detected for a long time because they develop very quickly and remain relatively short. And indeed, IRAS 00500 + 6713 is expected to collapse into a neutron star at some point within the next 1,000 years. It would “be with another, second supernova,” Oskinova said.