First double debris disk discovered around a white dwarf

An international team of astronomers led by Nicola Gentile Fusillo from the University of Trieste has discovered the first-ever observed double debris disk around a white dwarf. The research, published yesterday in Nature Astronomy, reveals that the dead star J1328-1450 is surrounded by two concentric rings of planetary material, separated by a distinct gap.

The unusual structure is likely shaped and maintained by two planetary bodies that survived the violent death of their parent star. According to estimates, the body in the inner ring is asteroid-sized, while the one in the outer ring could be as large as Pluto or even the Moon.

The observations, made with the X-shooter spectrograph of the ESO's Very Large Telescope in Chile, also show differences in the chemical composition of the two rings, suggesting that the materials come from two distinct planets or from different parts of a single celestial body.

White dwarfs are the dense, burnt-out cores that remain when Sun-like stars exhaust their nuclear fuel. During the final stages of their existence, these stars expand enormously, often engulfing and destroying the nearest planets. Rocky bodies that manage to survive this catastrophic phase can later fragment, giving rise to debris disks orbiting the dead star.

Until now, all debris disks observed around white dwarfs showed a single, flattened structure, identified through a specific observational "signature." The discovery of the J1328-1450 system completely breaks this pattern, revealing for the first time a dual configuration. This complexity suggests that some planetary systems can survive in modified forms even after the death of their central star.

The system also offers a glimpse into the possible future of our own Solar System. In billions of years, when the Sun becomes a white dwarf in turn, Earth and the other planets could face a similar fate, with some bodies potentially surviving and fragmenting into complex structures like the one just discovered.