In our cosmic neighborhood, about 260 light-years away, astronomers have uncovered a dramatic celestial event: a white dwarf star — the dense, burned-out core of a once Sun-like star — is devouring fragments of a Pluto-like icy world. This extraordinary discovery was made possible thanks to the ultraviolet vision of NASA’s Hubble Space Telescope, which detected signatures that ground-based telescopes simply cannot see.
A Stellar Remnant with an Appetite.
The white dwarf, though only about the size of Earth, packs half the mass of our Sun into its dense body. Its immense gravity tore apart an icy dwarf-planet fragment from the system’s Kuiper Belt analog — a ring of icy debris similar to the one beyond Neptune in our own solar system.
As the pieces spiraled inward, scientists analyzed their chemical makeup. What they found surprised them: volatile elements such as carbon, sulfur, nitrogen, and oxygen, including a massive fraction of water ice — about 64% of the object’s composition. This suggests the doomed body was not just a comet but a fragment of an exo-Pluto.
“We did not expect to find water or other icy content,” said Snehalata Sahu of the University of Warwick, who led the data analysis. “These volatile-rich objects are usually ejected when stars evolve into white dwarfs. Detecting such material is truly surprising.”
Nitrogen-Rich Like Pluto.
The team also detected an unusually high nitrogen content — the largest ever found in a white dwarf debris system. Pluto’s surface, for instance, is dominated by nitrogen ice. The similarities suggest the fragments accreted by the white dwarf may have come from the crust and mantle of a Pluto-like dwarf planet.
This discovery marks the first time astronomers have measured the composition of such an icy planetary fragment outside our solar system.
Hubble’s Unique View.
Ordinary telescopes, observing in visible light, would see nothing unusual. Only Hubble’s Cosmic Origins Spectrograph, working in ultraviolet light, can detect these volatile materials. That makes Hubble uniquely capable of revealing such interstellar feasts.
Astronomers hope to continue the investigation with the James Webb Space Telescope (JWST), which can probe for molecular features like water vapor and carbonates in the infrared.
A Glimpse of Our Sun’s Future.
This discovery also offers a chilling preview of what will happen in our own solar system. Billions of years from now, when the Sun becomes a white dwarf, it too will gravitationally shred Kuiper Belt objects. To alien observers, it may look much like what astronomers are now witnessing with this star.
“Measuring the composition of an exo-Pluto is an important contribution to understanding the formation and evolution of icy bodies,” said Boris Gänsicke, principal investigator of the Hubble program. “I’ve been thrilled to find a system that so closely resembles the frozen outer reaches of our solar system.”
Hubble’s Legacy.
For more than 30 years, the Hubble Space Telescope — a collaboration between NASA and ESA — has delivered ground-breaking insights into the cosmos. Managed by NASA’s Goddard Space Flight Center, with operations supported by Lockheed Martin Space and the Space Telescope Science Institute, Hubble continues to be a cornerstone of astronomical discovery.
With this new finding, Hubble not only expands our knowledge of white dwarfs and planetary remnants but also deepens our understanding of how water and life-supporting elements may travel across planetary systems.
