Astronomers using the European Southern Observatory's Very Large Telescope have detected an unusual double ring of planetary debris around a white dwarf star, which the study's lead author described as the first example of such a complex structure around a dead star. The system, J1328-1450, may be shaped by two surviving planetary bodies, including one potentially as large as Pluto or the Moon, according to a study published in Nature Astronomy.
The white dwarf is the dense remnant of a star similar to the Sun that expelled its outer layers at the end of its life. This transformation can be catastrophic for nearby planets: as the star swells, it may engulf worlds orbiting too close, while gravitational disturbances may eventually tear some more distant rocky objects apart. Their remains can form rotating discs of debris. Previously discovered debris discs around white dwarfs have consisted of a single ring, but J1328-1450 breaks that pattern with two concentric rings separated by a clear gap.
"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," said Nicola Gentile Fusillo, an astronomer at the Università degli Studi di Trieste and lead author of the study.
The researchers suspect that two surviving planetesimals, each in a separate orbit, are responsible for maintaining the gap. One, associated with the inner ring, is estimated to be only a few kilometres across, while the other could be as large as Pluto or Earth's Moon. Though not directly observed, their gravitational influence could help explain why the debris remains organised into two distinct rings rather than forming a single continuous disc.
Observations using the X-Shooter instrument on ESO's VLT in Chile's Atacama Desert revealed the chemical makeup of the rings. They contain calcium, oxygen, magnesium and iron, elements common in rocky planetary material, indicating that the rings contain remnants of solid bodies rather than simply gas left over from the star itself. The inner ring contains substantial amounts of magnesium gas, while the outer ring is largely depleted of it. This compositional difference suggests the two rings may contain remains of separate planets with different compositions, or material from different layers of the same world, for instance, one ring holding crust material and the other core material.
"The structure we see in this system is particularly intriguing because the two gaseous rings are remarkably stable and remain separated by a gap," said co-author Felipe Lagos-Vilches, an astronomer at the University of Warwick and the Universidad Técnica Federico Santa María. "The system is a rare glimpse of the violent, chaotic process by which a planetary system meets its end, and it hints that dead stars can have disc structures far more complex than previously realized," added Gentile Fusillo.
The discovery offers a possible preview of what could happen to our own Solar System billions of years from now, when the Sun becomes a white dwarf. “The system therefore offers a remarkable glimpse of what the future of planetary systems, including systems like our own, might look like,” Lagos-Vilches said.
Analysis
Why This Matters
- It provides the first direct evidence that planetary debris can form complex multi-ring structures around dead stars, revealing that the destruction of planetary systems can leave behind organised remnants.
- It supports the idea that some planetary bodies can survive the violent death of their star, raising questions about the long-term evolution of planetary systems.
- The chemical differences between the rings offer a unique window into the composition of destroyed planets, helping scientists understand the building blocks of rocky worlds across the galaxy.
Background
White dwarfs are the final evolutionary stage of stars like the Sun. After becoming red giants and expelling their outer layers, the remaining core is incredibly dense. Planets that orbit too close during this phase may be engulfed, while outer planets or smaller bodies can be torn apart by gravitational forces, forming a disc of vaporised debris. Until now, only single debris discs had been confirmed around white dwarfs. The discovery of a double disc around J1328-1450 suggests that the aftermath can be far more complex than previously thought.
What to Watch
- Whether future observations can directly image the two suspected planetesimals, confirming their existence and sizes.
- Searches for similar double-ring structures around other white dwarfs to determine how common such complex systems are.
- Analysis of the chemical differences between the rings to distinguish between separate destroyed planets and material from different layers of the same world.
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12 claims in this story checked against 1 source: 12 supported.
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- SupportedNicola Gentile Fusillo said: “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”.Latest Science News -- ScienceDaily: “"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," says Nicola Gentile Fusillo, an astronomer at the Università degli Studi di Trieste in Italy and lead author of the study”
- SupportedFelipe Lagos-Vilches said the two gaseous rings are “remarkably stable” and remain separated by a gap.Latest Science News -- ScienceDaily: “"The structure we see in this system is particularly intriguing because the two gaseous rings are remarkably stable and remain separated by a gap," says co-author Felipe Lagos-Vilches”
- SupportedGentile Fusillo called the system a rare glimpse of a planet system’s violent end and said it hints dead stars can have more complex disc structures than previously realised.Latest Science News -- ScienceDaily: “"The system is a rare glimpse of the violent, chaotic process by which a planetary system meets its end, and it hints that dead stars can have disc structures far more complex than previously realized," adds Gentile Fusillo”
- SupportedLagos-Vilches said the system offers a glimpse of what the future of planetary systems, including ours, might look like.Latest Science News -- ScienceDaily: “"The system therefore offers a remarkable glimpse of what the future of planetary systems, including systems like our own, might look like," concludes Lagos-Vilches.”
- SupportedThe double debris disc around a dead star hints at surviving worlds.Latest Science News -- ScienceDaily: “Even more surprising, the debris is divided into two distinct rings, with a clear gap between them that may be maintained by planetary bodies that somehow survived their star's death.”
- SupportedESO’s VLT observations reveal two distinct rings of planetary wreckage around white dwarf J1328-1450.Latest Science News -- ScienceDaily: “The discovery was made using the European Southern Observatory's Very Large Telescope (ESO's VLT). Unlike previously observed debris systems around dead stars, this one appears to contain two separate discs of material left behind by destroyed planets.”
- SupportedThe study’s lead author said the system may be shaped by two surviving bodies, one potentially as large as Pluto or the Moon.Latest Science News -- ScienceDaily: “Researchers believe two surviving objects may be shaping the unusual structure, including one potentially as large as Pluto or even the Moon. "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," says Nicola Gentile Fusillo”
- SupportedThe suspected survivors may maintain the gap: one associated with the inner ring is only a few kilometres across, while the other could be as large as Pluto or the Moon.Latest Science News -- ScienceDaily: “One of these objects, associated with the inner ring, is thought to be comparable in size to a typical asteroid, measuring only a few kilometers across. The other, farther from the star, could be much larger, potentially reaching the size of Pluto or even our Moon.”
- SupportedEarlier white-dwarf debris discs had a single-ring structure, while J1328-1450 has two concentric rings separated by a clear gap.Latest Science News -- ScienceDaily: “Instead of a single ring of vaporized planetary material, it has two concentric rings, meaning one lies farther from the star than the other. The rings remain clearly separated, creating an unusual structure”
- SupportedX-Shooter observations on ESO’s VLT in Chile’s Atacama Desert revealed the rings’ chemical makeup.Latest Science News -- ScienceDaily: “The evidence comes from observations collected with the X-Shooter instrument on ESO's VLT in Chile's Atacama Desert. The instrument analyzes light across a broad range of wavelengths, allowing astronomers to examine the chemical makeup”
- SupportedThe rings contain calcium, oxygen, magnesium and iron, indicating remnants of solid bodies rather than only gas left from the star.Latest Science News -- ScienceDaily: “Astronomers detected calcium, oxygen, magnesium, and iron, elements commonly found in rocky planetary material throughout our Solar System. Their presence indicates that the rings contain remnants of solid bodies rather than simply gas left over from the star itself.”
- SupportedThe inner ring has substantial magnesium gas and the outer ring is largely depleted of it; the difference may reflect separate planets or different layers of one world.Latest Science News -- ScienceDaily: “The inner ring contains substantial amounts of magnesium gas, while the outer ring is largely depleted of magnesium. This difference suggests that the material in the two rings may have originated from separate planets with different compositions. Another possibility is that both rings contain material from different layers of the same planetary body.”