Importance of disk-driven migration for close-in giants

Ascertain the importance of disk-driven migration in the formation of close-in giant exoplanets by quantifying its role under varying protoplanetary disk conditions relative to alternative migration channels.

Background

Multiple mechanisms could deliver giant planets to short-period orbits, including disk-driven migration and high-eccentricity tidal migration triggered by companions. The relative contribution of each mechanism remains debated in the literature.

The authors emphasize that disk-driven migration’s efficacy depends sensitively on disk properties and that its overall importance for producing close-in giants is uncertain, highlighting a broader, field-level unresolved question.

References

The details of disk-driven migration are highly sensitive to the disk conditions, and hence it is not clear how important this migration is for the formation of close-in giants \citep[e.g.][]{2014prpl.conf..667B,2021JGRE..12606629F}.

— TOI-6038 A b: A dense sub-Saturn in the transition regime between the Neptunian ridge and savanna  (2501.02272 - Baliwal et al., 4 Jan 2025) in Section “Formation and evolution scenarios”

However, no single model can satisfactorily account for all the observational evidence, and the formation pathway of hot Jupiters remains an open question.

— Are Hot Jupiters Tidally Disrupted During Stellar Main Sequence?  (2608.12790 - Hu et al., 13 Aug 2026) in Section 1, Introduction

With a sample of just five close-in GEMS with measured stellar obliquities that are all well-aligned, their dominant formation and migration channel remains an open question.

— New and Updated Rossiter-McLaughlin Measurements for Three Hot Jupiter-Hosting M Dwarfs  (2609.03031 - Weisserman et al., 2 Sep 2026) in Section 4.4, “Future Observations” (subsection “RM Observations of GEMS around Late M Dwarfs”)

Future constraints on outer companions and homogeneous samples will be key to determining whether the eccentricity distribution can robustly disentangle the dominant migration pathways of warm Jupiters.

— TS23/McDonald and FIES/NOT strike again. Two new warm Jupiter systems and outer companions in a third  (2609.30915 - Knudstrup et al., 25 Sep 2026) in Section 4.1.1, subsection “Warm Jupiter Eccentricity Distribution”

However, the origin of the warm Jupiter population is unclear (disc migration vs. planet-planet scattering) and might influence the heavy element content of the probed planets.

— The origin of the large heavy element contents of warm Jupiters  (2610.13762 - Bitsch, 9 Oct 2026) in Section 4.1, “General trends”