Suspected second-generation planet identified around white dwarf HS 0209+0832

Reexamining the white dwarf’s chemical fingerprint

A team led by University of Warwick researchers reportedly characterized a suspected exoplanet around the white dwarf HS 0209+0832, about 270 light-years away. The report says a reexamination found zinc, copper, and niobium in the white dwarf's chemical fingerprint, with niobium at more than 1,000 times the level in the Sun.

The researchers interpret this pattern as material processed in a dying star and as support for a planet formed after the star's earlier evolution. Brightness variations suggest the companion may be a Jupiter-sized gas giant in a 4.4-day orbit.

Hubble observations of HS 0209+0832 in 1999 revealed roughly 100 spectral lines that astronomers could not identify. The supplied report does not establish a comparable earlier characterization of a second-generation planet in this system.

A modern reexamination reportedly links the previously unexplained spectral signature to a chemical pattern that researchers interpret as evidence for a suspected planet formed from material shed by its white-dwarf parent.

An interpretation involving planet formation after stellar death

If the interpretation holds, the system would provide evidence that material expelled by a dying Sun-like star can form a new planet. It also offers a proposed explanation for spectral features that had remained unidentified since the 1999 observations.