Astronomers reexamining Hubble Space Telescope observations from 1999 found an unusual abundance of niobium around the white dwarf HS 0209+0832. By matching previously unidentified spectral features against an updated chemical database, the team developed evidence that the system may contain a second-generation planet.

A second-generation planet would form from material released late in a star’s life rather than from the disk present when the star was born. The researchers propose that enriched material expelled by the dying star collected into a gas giant while the rest of the debris dispersed.

Data from NASA’s retired Far Ultraviolet Spectroscopic Explorer also showed strong niobium signatures. Observations from the TESS mission found periodic brightness changes consistent with an object orbiting about 6 million kilometers from the white dwarf, and the team estimates the candidate is roughly Jupiter-sized.

The hot white dwarf appears to be stripping atmosphere from the possible planet, sending material back toward the star where Hubble can detect it. The interpretation is not yet a direct image or final confirmation of the planet, and the researchers plan additional observations to learn how such systems form and evolve.