The phoenix planet: Astronomers find a world reborn from its star's ashes

KUALA LUMPUR, 5 OCTOBER 2026 —

Astronomers have announced the discovery of the first second‑generation planet orbiting a white dwarf, a world that appears to have formed from the remnants of the dead star it now circles.

The finding is significant because it demonstrates that planets can form from material ejected by a dying star, a process previously suspected only around pulsars. White dwarfs are the collapsed cores left when stars exhaust their fuel, and they are known to accrete material from nearby bodies. The chemical fingerprints left in a white dwarf’s atmosphere can reveal the composition of orbiting planets.

In the case of HS 0209+0832, the atmosphere contains unusually heavy elements—zinc, copper and, most notably, niobium—at levels over 1 000 times higher than the Sun’s. Niobium had never before been detected in a white dwarf, making the signature a clear indicator of material processed in a dying star.

Dr. Nicholas Stone of the University of Wisconsin‑Madison explained that the pattern of elements is a telltale sign of the “s‑process,” a nuclear reaction that builds heavy elements inside dying stars during their red‑giant phase. “It’s a chemical signature no ordinary, first‑generation planet should carry,” Stone said, adding that the presence of these elements indicates a planet formed from the star’s own expelled material.

The Warwick team proposes that the white dwarf is feeding on a newly formed, second‑generation giant planet that condensed from a disk of material created during the star’s death. Because the disk was made from the star’s own ejected matter, it would naturally be rich in the unusual heavy elements now seen in the white dwarf’s atmosphere. Williams, the study’s first author and a Ph.D.

student in the Department of Physics at Warwick, noted that forming such a protoplanetary disk is difficult. “A single, isolated star dies and sheds mass in a roughly symmetrical way,” he said. “To form a disk of material necessary to birth a planet, HS 0209+0832 likely required a companion star that pulled the ejected material back into orbit, rather than letting it escape.”

Data from NASA’s Transiting Exoplanet Survey Satellite (TESS) provided further evidence. Researchers detected a faint, regular brightness signal directly from the planet that repeated every 4.4 days, consistent with a Jupiter‑sized gas giant tidally locked in a tight orbit.

At such a close distance from the white dwarf, the planet’s outer atmosphere is expected to be evaporating under intense radiation, with the escaping material raining down onto the white dwarf’s surface and producing the unusual chemical signature.

If confirmed, HS 0209+0832 would be the first white dwarf known to host a second‑generation planet, opening a new avenue for searching for similar reborn worlds. By looking for the same carbon and heavy‑element signatures in the light of other dead stars, astronomers could identify additional systems where planets have formed from stellar ejecta.

Professor Boris Gänsicke of Warwick’s Department of Physics summed up the implications: “What’s remarkable about the planet around HS 0209+0832 is that this isn’t a planet from somewhere else, or a survivor from the system’s birth; it looks like it was built from the very material its own star cast off as it died.” He added that the discovery raises the question of how many more such planets might exist and whether our own solar system could host a second‑generation planet formed from the ashes of the Sun.

Related: University of Warwick · Professor Boris Gänsicke