Giant-planet hosts born in inner Galaxy while rocky systems show smaller radial excursions in arXiv 2607.07787 analysis
Preprint maps exoplanet hosts to Galactic birth radii using Gaia and chemical models. Giant hosts favor inner birth sites; rocky systems are less concentrated. Findings connect formation pathways to galactic evolution but remain limited by detection biases.
The study integrates stellar orbits via Galpy and infers birth radii for hosts using generalized additive models combined with Galactic chemical evolution tracks. It separates populations by architecture: giant-planet hosts cluster toward inner birth sites, brown-dwarf hosts display broader displacements, and rocky systems remain more locally confined. Outward migrators show more compact outer companions than inward migrators, though detection biases remain heterogeneous.
These patterns link planet formation efficiency to local metallicity and dynamical heating, implying inner-disk conditions favor gas giants while outer or mixed environments permit rocky worlds. Older ages among rocky and rocky-plus-giant hosts position them as reference samples for habitability studies. The absence of a clear radial-displacement versus multiplicity correlation suggests migration imprints are architecture-specific rather than universal.
Future Gaia DR4 kinematics and high-resolution spectroscopy of 200+ additional hosts will test whether these birth-radius trends persist after bias corrections, tightening constraints on both core-accretion models and Galactic chemo-dynamical simulations.
Dantas et al.: Gaia DR4 release in 2027 will detect radial migration signatures at >3-sigma in at least 120 confirmed hosts after bias homogenization.
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2607.07787)
- [2]Supporting Source(https://arxiv.org/abs/2301.07792)