Astronomers Find 4.4-Day Planet Candidate Feeding White Dwarf HS 0209+0832
Updated
Updated · Sci.News · Oct 7
Astronomers Find 4.4-Day Planet Candidate Feeding White Dwarf HS 0209+0832
3 articles · Updated · Sci.News · Oct 7
Summary
HS 0209+0832, a 5-million-year-old white dwarf 270 light-years away, appears to be accreting material from a possible second-generation giant planet rather than shattered asteroids.
Reanalyzed Hubble, VLT, FUSE, Gaia and Pan-STARRS data showed niobium more than 1,000 times the Sun’s abundance and nickel at least twice iron—an elemental mix unlike meteorites or 33 other polluted white dwarfs.
Those abundances match models of heavy elements forged during the star’s asymptotic giant branch phase, supporting the idea that a disk from stellar winds later formed a new planet.
TESS detected a repeating 4.4-day brightness signal, much longer than a typical 1.25-day white-dwarf spin, consistent with a close-orbiting gas giant at about 0.04 AU.
The Nature Astronomy study suggests planetary systems may keep forming after a star dies, extending the timeline for habitable-zone worlds around cooling white dwarfs.