Possible planet formed from dead star’s remnants
A candidate gas giant orbiting a white dwarf appears to contain material from its dead star.
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Astronomers have found evidence of a planet that may have formed from material expelled by a star during the final phase of its life. The candidate orbits the white dwarf HS 0209+0832, but further research is needed to determine whether this interpretation holds up.
The peer-reviewed study was published in Nature Astronomy on 5 October. The researchers analysed ultraviolet light previously measured by the Hubble Space Telescope, among other data, and combined it with observations from NASA’s TESS space telescope.
They found unusually high quantities of heavy elements in the white dwarf’s atmosphere, including zinc, copper and niobium. At the same time, elements common in rocky planets, such as silicon and iron, were less strongly represented. According to the study, this combination is consistent with material formed during a star’s red-giant phase.
The researchers believe the star expelled gas during its evolution. That material may have ended up in a disc around the white dwarf, from which a new planet could then have formed. The researchers call such a planet a so-called second-generation planet: it does not form from the original disc around the star, but from stellar material expelled later.
TESS detected a periodic signal from the system of about 4.4 days. The researchers attribute it to a Jupiter-sized gas giant close to the white dwarf and rapidly losing atmosphere because of the intense radiation. The signal may also be linked to material flowing away from the planet; for that reason, the authors refer to it as a candidate.
The observations are not a direct image of the planet. The conclusion is based on the white dwarf’s chemical composition, the periodic light signal and models of how stars expel material. Another explanation for some of the data cannot be completely ruled out.
The discovery is particularly interesting for models of planet formation. It shows that a planetary system may enter a second phase after its original star has shed its outer layers. The researchers themselves stress that it remains unclear how common such planets are and whether this case can be definitively confirmed as a planet through additional observations.
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The scientific status is correctly presented as peer-reviewed candidate research. The text makes clear which observations were made and which conclusions still depend on models.
- confirmed The study was published in Nature Astronomy on 5 October 2026. — Nature gives the publication date and identifies the article as open access. source
- confirmed The white dwarf contains unusual quantities of zinc, copper and niobium. — This is stated in the study’s abstract and main text. source
- confirmed The periodic signal is approximately 4.4 days. — Nature reports 4.399 plus or minus 0.026 days. source
- confirmed The planet is still a candidate and has not been definitively confirmed. — The study’s title and conclusion refer to a candidate second-generation planet. source
Editor's note
The research is peer-reviewed, but the planet remains a candidate. Its origin in stellar material is a scientific interpretation of chemical and photometric evidence.Sources
- Discovery of a second-generation planet candidate accreting onto a white dwarf — Nature Astronomy
- Suspected second-generation planet solves Hubble cold case — NASA Science
- The phoenix planet: astronomers find a world reborn from its star’s ashes — European Research Council
More on this in Dutch media
- De Telegraaf — „astronomie exoplaneet”
- AD — „astronomie exoplaneet”
- de Volkskrant — „astronomie exoplaneet”