Researchers say the hot white dwarf HS 0209+0832 is actively accreting material from a planet candidate whose chemistry does not match any known Solar System body.
Ultraviolet spectra show strong zinc, copper and especially niobium enrichment, but only trace silicon and no iron—an s-process-heavy pattern consistent with material formed from asymptotic giant branch ejecta after the star’s main-sequence life.
TESS data add a 4.399-day, 0.120% brightness modulation, which the team links to either thermal emission from a close-in gas giant at about 0.04 AU or an evaporating comet-like tail crossing the line of sight.
High-energy radiation from the roughly 35,800 K white dwarf could drive atmospheric escape fast enough to feed the measured accretion rate above 4.45 × 10^8 grams per second.
If confirmed, the system would be the first white-dwarf example of a second-generation planet, suggesting some close-in planets can form after a star dies rather than only survive from the original system.