A study published on Monday titled "Discovery of a second-generation planet candidate accreting onto a white dwarf" has revealed a Jupiter-sized gas giant orbiting the white dwarf HS 0209+0832. Researchers re-examined Hubble Space Telescope observations from 1999, which had detected carbon, aluminum, silicon, calcium, titanium, nickel, and zinc in the star's atmosphere, along with about 100 unidentified spectral lines.
Using new techniques, the team identified the mystery matter as niobium, an element heavier than iron that is not formed by thermonuclear fusion in stellar cores. Co-author Nicholas Stone, a theoretical astrophysicist at the University of Wisconsin, told NASA: "Niobium and other elements heavier than iron are astronomically special because, unlike many common elements, they are not formed in the cores of stars by thermonuclear fusion. Instead, these heavy elements can only be synthesized in the exotic conditions that briefly emerge inside dying stars. The presence of niobium is a signpost of these 'death' throes, and the expulsion of the dying star's innards into space."
The planet's composition does not match any known rocky material around white dwarfs or meteorites in our Solar System, indicating a new type of planetary material. The white dwarf is stripping the planet's atmosphere, potentially creating a comet-like tail that forms a disk around the star and falls back onto its surface, which is how Hubble detected the niobium.
Co-author Jamie Williams, from the University of Warwick, expressed optimism about the planet's survival: "If the second-generation planet is there, I think it is likely to survive. Eventually the white dwarf will cool and then maintain a consistent temperature, with the planet in its stable habitable zone for millions of years."