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Warwick astronomers identify a possible planet formed from a dying star's material
A University of Warwick-led team has found evidence that white dwarf HS 0209+0832 may host a second-generation planet formed from material expelled during the star's death.
Astronomers led by the University of Warwick in England have identified evidence for a possible second-generation planet around white dwarf HS 0209+0832. Their interpretation is that the planet formed from material its star expelled as it died, rather than surviving from the original planetary system.
A white dwarf is the collapsed core left after a star exhausts its fuel. Such stars can draw in material from nearby planets, leaving chemical traces in their atmospheres. The study, published in Nature Astronomy, found unusual abundances of heavy elements in this white dwarf, including zinc, copper and niobium at levels more than 1,000 times those in the Sun.
Data from NASA's TESS satellite also showed a faint brightness signal repeating every 4.4 days. Researchers described it as consistent with a Jupiter-sized gas giant in a tight, tidally locked orbit. They expect intense radiation to strip material from its outer atmosphere, with that material falling onto the white dwarf and producing the chemical signature.
The team's favored explanation is that the planet condensed from a new disc of material shed during the star's death. Confirmation remains necessary: if established, the system would be the first white dwarf found to host a second-generation planet.