TEHRAN (Iran News) – Researchers revealed Sunday they have discovered a new star system that belongs to one of the rarest star types in the known universe, but experts say it is unlike anything they have seen before.
Of all the numerous and wide-ranging types of stars astronomers and astrophysicists have discovered throughout history, perhaps one of the rarest is a star type known as the Wolf-Rayet, Court House News reported.
First discovered by Charles Wolf and Georges Rayet in the late 1860s, Wolf-Rayet stars are intensely bright and hot stars that, due to their unique makeup, are destined to ultimately collapse on themselves in a supernova explosion that will leave behind nothing but a dark void.
This violent and explosive death for the star type sets it somewhat apart from other forms of star decay, such as white dwarfs that experience a more drawn out and protracted death. The stars are so unique, in fact, that among the cosmos only one in a hundred million stars are classified as a Wolf-Rayet.
While these types of systems are rare enough in their own right, there exists a small and elite group among Wolf-Rayet stars that are even rarer.
These are binary pairs of Wolf-Rayet stars that can produce massive amounts of carbon-based dust that are whipped about by stellar winds, and as the binary Wolf-Rayet stars orbit around one another, the cosmic dust forms a glowing and luminous tail that wraps around the two sister stars.
This intensely rare and beautiful phenomena can only be made possible under the most precise and astronomically unlike conditions, explaining why only a small handful of them have ever been discovered.
Two years ago, this exclusive club welcomed a new member when researchers discovered a star system roughly 8000 light years from Earth that met this qualification, but after further examination, new research shows that it behaves in a way that is unlike any other Wolf-Rayet system experts have ever come across.
In a study published Sunday in the scientific journal Monthly Notices of the Royal Astronomical Society, researchers reveal that they have studied the newly discovered star system, dubbed Apep after the snake-like Egyptian god of chaos, using advanced imaging techniques at the European Southern Observatory’s Very Large Telescope at Paranal in Chile.
Their findings suggest that the Wolf-Rayet is aptly named.
This is due to the fact that like all binary pairs of Wolf-Rayet stars, Apep comes equipped with a swirling spiral of dust that surrounds it, but unlike other Wolf-Rayet systems the dust seems to have a mind of its own.
Rather than swirl with the speed of stellar winds that push it along, the cosmic dust around Apep floats along at a remarkably slower speed than the surrounding winds should dictate — an astrological anomaly.
Researchers made this perplexing discovery by constructing a detailed model that could replicate Apep’s complex spiral structure for the first time, a feat that allowed scientists to study its beautiful but unheard-of behaviors.
Yinuo Han, University of Sydney honors student and lead author of the study who completed the paper while on COVID-19 lockdown, said that the behavior of the newly discovered star left researchers mystified.
“Aside from the stunning image, the most remarkable things about this star system is the way the expansion of its beautiful dust spiral left us totally stumped,” Han said with the release of the study.
While this difference between the speed of the dust spiral and the speed of the surrounding winds is scientifically baffling, it is also extremely noticeable.
Using the newly created model, researchers calculate that the speed of the dust is around four times slower than the speeds of the stellar winds, a significant discrepancy that has never been observed in a star system until now.
A closer look at Apep’s makeup further solidifies the accuracy of its namesake. The two stars that make up the Wolf-Rayet system are around 10 to 15 times larger than the Sun, not to mention more than 100,000 times brighter.
The stellar winds themselves are also highly extreme in nature, with experts saying they are coming off Apep at around 12 million kilometers an hour, roughly 1% the speed of light.
Researchers suggest that it is perhaps the wind speed and the speed at which the stars rotate that could potentially explain the confusing dust movement.
“It likely means that stellar winds are launched in different directions at different speeds,” Han said. “The dust expansion we are measuring is driven by slower winds launched near the star’s equator.”
Researchers are also speculating on what the future of Apep may hold — a future that is likely to be quite destructive.
Data shows that on top of carrying all of the typically extreme characteristics of a Wolf-Rayet, Apep’s main star seems to rotate at remarkable speed, potentially giving it the ability to detonate a long gamma-ray explosion when the system ultimately goes supernova.
This potential future could prove disastrous for nearby systems, given that gamma-ray bursts are some of the most energetic natural events in the known universe.
These bursts are so potentially deadly that if such a burst were to ever strike Earth, the force from the blast could destroy the ozone layer around our planet that acts as a protective shield from the radiation of the Sun.
Researchers say, however, that there is no reason for anyone to fear Apep’s explosive potential. Due to the star system’s axis of rotation, any future blasts would not come within striking distance of Earth.
- source : Tasnim, Iran News