A dead star's double debris disk may be shaped by two surviving planetary bodies

With the European Southern Observatory's Very Large Telescope (VLT) in Chile, astronomers have found a white dwarf, the dense leftover core of a star like the Sun, surrounded by the remains of destroyed planets arranged in two separate rings. The team proposes that two planetary bodies that survived the star's death keep the rings apart. The study was published in Nature Astronomy on October 26, 2026, and ESO announced it on October 27.

The star, WD J1328−1450, lies about 500 parsecs, or roughly 1,600 light-years, from Earth. The team first noticed it because it gives off more infrared light than a bare white dwarf should, a sign of a dusty disk. Its spectrum also shows calcium, magnesium and silicon absorbed into the star's atmosphere, which confirms that it is pulling in planetary material from that disk.

Four peaks instead of two

Gas orbiting a white dwarf shows up as emission lines in its spectrum. Only 0.067% of white dwarfs show such gas disks, and in all 21 previously known examples the lines have two peaks, the signature of a single flat, rotating disk. In WD J1328−1450, the calcium and oxygen lines have four. The researchers explain this as light from two concentric rings: an inner one from 0.14 to 0.34 times the Sun's radius from the star, and an outer one from 0.54 to 1.93 solar radii. The line shapes did not change between spectra taken in 2021 and 2023, which supports a stable, nearly circular structure.

The two rings also differ in makeup. The gas contains calcium, oxygen, magnesium and iron, a mix similar to rocky material in our Solar System, but the inner ring is rich in magnesium and the outer one largely lacks it. That suggests the material came from two planets of different composition, or from different layers of a single body, such as a magnesium-rich mantle and a magnesium-poor crust.

We have known for some time that planets may survive beyond the transformation of their central star, but this is the first example of a complex system with a double debris disc and potentially two surviving planetesimals.

Two survivors

Around another white dwarf, SDSS J1228+1040, a regular two-hour signal in the gas has been explained by a dense solid body embedded in the disk that makes gas as it interacts with the dust. The authors argue that the same mechanism is the most likely source of the gas here, so two separate gas rings would need two bodies on concentric orbits. To avoid being torn apart by the star's gravity so close in, those bodies must be very dense or internally strong. The team estimates the inner one could be at most the size of a typical asteroid, while the outer one's maximum size could range from that of Ceres, the largest asteroid, to that of Pluto or even the Moon, depending on how far from the star it orbits.

Other explanations

The authors weighed alternatives. A single, vertically thick disk that shadows part of itself between 0.34 and 0.54 solar radii could produce similar line shapes, but no existing theoretical model backs that scenario, they write. Two white dwarfs too close together for the Gaia mission to separate, each with its own disk, could also give four peaks. The team calls that unlikely, because gas disks are so rare that two forming at once in one system would be an extreme coincidence. A single body clearing a gap in one disk is also considered, but it would make the system's strong infrared glow harder to explain.

A preview of the Solar System's end

The Sun will itself become a white dwarf in the far future, in a process that may destroy Earth, ESO notes. Gas disks like this have been known for about 20 years, but how they form and change over time is still poorly understood, the authors write, and the double disk gives modelers new limits to work with.