Formation mechanisms and demographics of cold Jupiters

Determine the formation mechanisms of cold Jupiter exoplanets by establishing their core masses, reconstructing their migration histories, and measuring their occurrence rates across different stellar environments.

Background

Cold Jupiters are giant planets beyond roughly 1 au that are thought to form near or beyond the snow line under core accretion, yet their detailed origins are not well constrained.

The paper highlights that key aspects of cold Jupiter formation and population statistics remain unresolved, motivating joint radial-velocity and astrometric analyses to expand the sample with well-constrained masses and three-dimensional orbits.

References

However, the precise formation mechanisms of cold Jupiters remain uncertain, with open questions regarding their core masses, migration histories, and overall occurrence rates across different stellar environments.

— Detection of four cold Jupiters through combined analyses of radial velocity and astrometry data  (2601.11280 - Wu et al., 16 Jan 2026) in Introduction (Section 1)

It is currently unclear whether a physically motivated minimum or maximum core mass exists, or whether the diversity of formation pathways makes such a threshold fundamentally degenerate.

— Beyond Pebble Isolation: Diverse Pathways to Giant Planet Formation Across Stellar and Orbital Scales  (2609.09382 - Peerani et al., 8 Sep 2026) in Section 7, “Limitations and Future Work”