White Dwarf Creates Mysterious Colourful Shockwave in Space
Astronomers have discovered a highly magnetised white dwarf producing a striking, multicoloured shockwave as it travels through space, leaving researchers searching for an explanation. The phenomenon, observed about 730 light years away in the constellation Auriga, adds a fascinating new chapter to the study of stellar remnants.
A Compact Star with a Powerful Companion
The white dwarf, an extremely dense stellar remnant roughly the size of Earth, is gravitationally bound to a red dwarf companion in a binary system. As the two stars orbit closely—about the distance between Earth and the Moon—the white dwarf siphons gas from its smaller partner. The system, relatively nearby in cosmic terms, lies within our Milky Way galaxy.
White dwarfs form when stars up to eight times the mass of the Sun exhaust their nuclear fuel. They collapse under their own gravity, shedding their outer layers and leaving behind a dense core. Although not as compact as black holes, white dwarfs rank among the densest known cosmic objects. The Sun is also expected to end its life as a white dwarf, though not for billions of years.
A Brilliant Shockwave Captured
Using the European Southern Observatory’s Very Large Telescope in Chile, scientists captured an image of the glowing shockwave, or bow shock, formed as material from the white dwarf collides with surrounding interstellar gas. The colours represent different excited elements: red for hydrogen, green for nitrogen and blue for oxygen.
“A shockwave is created when fast-moving material ploughs into surrounding gas, suddenly compressing and heating it. A bow shock is the curved front that forms when an object moves rapidly through space, similar to the wave in front of a boat,” explained astrophysicist Simone Scaringi of Durham University, co-lead author of the study published in Nature Astronomy.
“The colours come from interstellar gas that is being heated and excited by the shock. Different chemical elements glow at specific colours when this happens,” Scaringi added.
A Cosmic Mystery
Although a few other white dwarfs have shown similar shockwaves, those examples were surrounded by discs of gas siphoned from their binary partners. This system, however, shows no such disc. While gas is being drawn from the red dwarf companion and channelled along magnetic field lines to the white dwarf’s poles, this process alone cannot explain the powerful outflow required to form the observed shockwave.
“Every mechanism with outflowing gas we have considered does not explain our observation, and we still remain puzzled by this system, which is why this result is so interesting and exciting,” Scaringi said. He added that the shape and size of the bow shock suggest the process has persisted for at least 1,000 years.
Beyond its scientific significance, Scaringi described the display as a vivid reminder of the universe’s dynamism. “Space is not empty or static as we may naively imagine it—it is dynamic and sculpted by motion and energy,” he said.
with inputs from Reuters
