In a discovery that could change scientists' perception of the end of planetary systems, a team led by the University of Warwick in Britain has found the strongest evidence yet of a "second-generation planet" around a white dwarf, that is, a world that did not form with its star at the beginning, but was born from the material that the star ejected during its dying.
The significance of this discovery lies in the fact that it presents the first known candidate of its kind around a white dwarf, and opens up the exciting possibility that the death of Sun-like stars may not mark the end of planet formation. The findings were published in the journal Nature Astronomy on October 5, 2026.
The star's atmosphere displayed elements such as carbon, silicon, calcium, nickel, and zinc, along with approximately 100 spectral lines whose origins scientists were then unable to determine. As knowledge accumulated about white dwarfs contaminated by planetary remnants, researchers revisited this long-standing question, discovering that one of the keys was a rare element: niobium.
A chemical fingerprint reveals the origin of the New World
A white dwarf is the hot core that remains after a low-mass star runs out of fuel and loses its outer layers. When stars similar to the Sun reach the end of their lives, they expand to become red giants and then eject enormous amounts of their material before their cores collapse.
The cooling age of "HS 209" is about 5 million years, while its surface temperature reaches about 35,000 Kelvin.
Researchers found an unusual abundance of zinc and copper in its atmosphere, and most importantly, niobium—a signature associated with a nuclear process known as slow neutron capture, or S-process. These heavy elements are produced inside stars during their final stages, making their presence in a planet that formed alongside the star from its birth difficult to explain.
Researcher Nicholas Stone of the University of Wisconsin-Madison's Department of Astronomy said that this signature "shouldn't be present in a typical first-generation planet," leading the team to a more unusual scenario: that the material ejected by the dying star later coalesced to form a new planet. The study suggests that the presence of a companion star may have helped keep the ejected material in an orbit that allowed it to form a disk and then a planet.
A gas giant and a future that may await the sun
Data from the TESS satellite supported the scenario; researchers detected a periodic change in the system's light consistent with a nearby object completing its orbit in about 4.4 days, and the results indicate that it is a gas giant about the size of Jupiter.
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