Origin of the hot-Jupiter period overdensity

Determine whether the observed overdensity of hot Jupiters at orbital periods of approximately 1–10 days is an intrinsic outcome of planet formation or primarily the result of observational biases.

Background

The simulations find that in-situ formation and the migration prescriptions considered do not reproduce the shortest-period giant planets. The paper therefore identifies the observed concentration of hot Jupiters at periods of roughly 1–10 days as an unresolved issue and asks whether it reflects genuine formation physics or a feature of the detection process.

References

A key outstanding question is the physical origin of the observed overdensity of hot Jupiters at orbital periods of approximately 1--10 days and whether this feature reflects an intrinsic outcome of planet formation or is primarily the result of observational biases.

— 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”