A Giant Beside a White Dwarf

Astronomical evidence

WD 1856+534 b passes in front of a white dwarf every 1.4079405 ± 0.0000011 days. White dwarfs are compact stellar remnants. The combination of a giant planet and a small host produces a distinctive transit geometry, and the close present orbit raises questions about the planet’s history after the host’s red-giant phase. A 2026 JWST analysis reports an atmosphere containing hydrocarbons and aerosols, with thermal emission from the planetary nightside. Its spectral models constrain the mass to 4.3–10.9 Jupiter masses. These are model-dependent atmospheric constraints, not a direct weighing of the planet. The saved composite table retains an older entry of 4386.054 Earth masses without an upper-limit flag. That discovery-era value should be read as an old upper constraint, not an exact measured mass. The newer study is identified separately so the differing provenance remains visible.

The illustrated viewpoint

The broad cloud bands, nearby observing platform and apparent sizes are artistic choices. The atmospheric detections do not provide a resolved weather map, and the image does not choose between competing migration histories.

The broad cloud bands, nearby observing platform and apparent sizes are artistic choices. The atmospheric detections do not provide a resolved weather map, and the image does not choose between competing migration histories. All depicted life and technology are fictional.

Catalog measurements & sources

Host: WD 1856+534. Snapshot: 25 September 2026. Errors, limits and source provenance are retained. Calculated values and model estimates are not direct measurements. Unknown is not zero; equilibrium temperature is not surface temperature.

References

• NASA Exoplanet Archive · WD 1856+534 b · composite snapshot, 25 September 2026
• Vanderburg et al. 2020 · discovery
• MacDonald et al. 2026 · atmosphere and mass constraints
• Vanderburg et al. 2020
• TICv8