The strange dead star

Gas and dust flowing from stars sometimes collide with the environment of another. Thus they create a shock wave. But they must meet certain conditions for it to happen. That's why astronomers are intrigued by the strange dead star that has a beautiful shock wave around it. It shouldn't be there.

This discovery is enigmatic and impressive. It challenges our understanding of how dead stars interact with their environment. "It's something never seen before and, more importantly, totally unexpected." This is stated by Simone Scaringi, professor at the University of Durham (United Kingdom). "Our observations reveal a powerful outflow that, according to our current understanding, should not be there."

The strange dead star generates a peculiar shock wave.

Thousand years of broadcast

The star in question is located 730 light years away. Like the Sun and other stars, it revolves around the center of our galaxy. As it moves, it interacts with the gas that permeates the space between the stars. It creates a type of shock wave called a bow wave, "a curved arc of material, similar to the wave that forms in front of a ship," they explain. The star is a white dwarf (the residual core of a dying low-mass star). It has a Sun-like companion orbiting it.

The shape and size of the bow wave imply that the white dwarf has been expelling powerful outflow for at least 1,000 years. The scientific community does not know exactly how a dead star without a disk can drive such long-lasting emission. This white dwarf is known to have a strong magnetic field, which has been confirmed by MUSE data. This field channels material stolen from the companion star directly toward the white dwarf, without forming a disk around it.

Shock waves are a common phenomenon, but this is the first of its kind.

secret engine

'Our finding shows that even without a disk, these systems can generate powerful emissions. It is a mechanism that we still do not understand. "This discovery challenges the standard picture of how matter moves and interacts in these extreme systems." The results suggest a hidden source of energy, probably the strong magnetic field. They have not yet determined what that 'mysterious engine' of the strange dead star is. The enigma persists, but they await answers from the observation of similar systems.