A small piece of a dead star, located just 731 light-years away, has left astronomers puzzled with a dazzling phenomenon: a bright, glowing bow shock.
While such a feature might not be unusual in other cases, the white dwarf RXJ0528+2838 shows no apparent mechanism to explain the colorful nebula encircling it.
Quiet Star Shocks Astronomers with Stunning Nebula
“We discovered something never seen before—and completely unexpected,” says Simone Scaringi, an astronomer at Durham University in the UK. “The fact that a supposedly quiet, diskless system could produce such an extraordinary nebula was one of those rare ‘wow’ moments.”
White dwarfs are the remnants of stars similar to the Sun after they finish their main-sequence phase. After fusion stops, a star’s core collapses into a dense white dwarf, ejecting its outer layers.
Although roughly the size of Earth, white dwarfs can contain up to 1.4 times the mass of the Sun. They often exist in binary systems, siphoning material from a companion star, which can trigger phenomena like repeated thermonuclear eruptions.
Companions Can Create Swirling Disks Around Windless White Dwarfs
Since white dwarfs no longer fuse atoms, they cannot generate stellar winds like active stars. However, interactions with a companion can form a disk of material around the white dwarf, swirling like water going down a drain.
When outflows from this disk collide with the surrounding interstellar medium, they create energetic structures called bow shocks.
In the case of RXJ0528+2838, there is a low-mass companion star but no disk. “The bow shock’s structure and emissions suggest a steady 1,000-year outflow, unlike sudden thermonuclear bursts.”
Magnetic Fields Channel Material Without a Disk
The researchers suggest that the white dwarf’s strong magnetic field might be preventing a disk from forming. Instead, material from the companion star could be channeled along the magnetic field lines and deposited directly onto the white dwarf, producing outflows without the need for a disk.
“Our observations show a strong outflow that, based on what we know, shouldn’t exist,” says astronomer Krystian Ilkiewicz from the Nicolaus Copernicus Astronomical Center in Poland.
“This discovery demonstrates that even without a disk, these systems can produce powerful outflows, revealing a process we don’t yet understand. It challenges the traditional understanding of how matter behaves and interacts in such extreme binary systems.”
Read the original article on: Sciencealert
Read more:Atlas Humanoid Robots will be Deployed in Hyundai Factories