Stars are supposed to have one act, then an epilogue. A star like our Sun is born, shines for billions of years, swells into a red giant, and then sheds its outer layers, leaving behind a small, hot remnant called a white dwarf. Any planets that formed at the star's birth must survive that upheaval — or not. What nobody expected was a second act: a brand-new planet forming from the material the dying star threw off.
That is the possibility raised by a study published in Nature Astronomy and announced by ESA and NASA on 5 October 2026. It is a candidate, not a confirmed sighting of a planet itself. The evidence is chemical, and it comes from a cold case in an archive.
In 1999, the NASA/ESA Hubble Space Telescope observed a white dwarf star called HS 0209+0832. Its data contained roughly 100 chemical features that could not be identified at the time. More than a quarter of a century later, Jamie Williams, a doctoral candidate at the University of Warwick, went back to those records with an updated chemical database. He found that niobium — an element used on Earth in jewellery and medical imaging devices — matched many of the mystery features. Niobium had not been reported in any other white dwarf analysed to date.
Niobium matters because of where it comes from. Niobium and other elements heavier than iron are not formed in stars by ordinary thermonuclear fusion. They can only be made in the exotic conditions that briefly emerge inside dying stars. Finding a high abundance of niobium therefore points to material that was enriched by the star's death and then expelled into space — not material left over from the star's birth.
The team's theory is that some of that ejected, enriched material coalesced into a gas giant planet, about the size of Jupiter. The rest of the ejected material dispersed long ago, but the planet remains. The idea was checked against other telescopes: data from NASA's retired FUSE mission also showed strong signatures of niobium in the same system, and NASA's TESS satellite watched the white dwarf for four months and detected periodic brightness variations indicating a planet orbiting at about 6 million kilometres — much closer than Mercury orbits the Sun.
Because the white dwarf is relatively new, it is still very hot. The researchers estimate the candidate planet is rapidly losing atmosphere under that blast of energy, which could give it a comet-like tail of material falling back onto the star — one reason Hubble could detect the niobium when studying the star. Even so, Williams said that if the planet is there, it is likely to survive: eventually the white dwarf will cool, and the planet could sit in a stable habitable zone for millions of years.
There is still a lot of work to do, as the researchers themselves stress. This is the first candidate with the hallmarks of a planet formed from material related to a star's death, rather than its birth. How such planets form, how common or rare they are, and how they evolve around a dead star are all open questions. Williams plans to use Hubble to explore them over the next several years.
For students, the story is also about how science uses old data. The clue was sitting in an archive from 1999, waiting for a better chemical database and someone patient enough to look again. Discovery is not always a new telescope pointing at a new sky. Sometimes it is an old measurement, understood at last.
If your child looks up at the night sky and asks how stars live and die, a first lesson in physics can take them from that question to the evidence — what a white dwarf is, why elements are fingerprints, and how astronomers test an idea without ever seeing the planet itself, with booster and mock-exam help in physics along the way. Book your first lesson
Sources:
- ESA/Hubble, "Suspected second-generation planet solves Hubble cold case", Science Release heic2613, 5 October 2026: https://esahubble.org/news/heic2613/
- Williams, J., et al., Nature Astronomy (2026), study of white dwarf HS 0209+0832, as reported in the ESA/Hubble release above.