The effect of stellar position-velocity clustering on exoplanet properties and demographics

Abstract: Recent studies suggest that stellar phase-space (position-velocity) clustering may shape planetary system architectures, with hot Jupiters preferring hosts in over-dense phase-space environments. The origin of the detected correlation remains debated: explanations include known correlations between stellar and planet properties (e.g. stellar metallicity and planet mass), age dependencies, and Galactic perturbations triggering inward migration. Using precise stellar astrometry, we re-calculate the phase-space densities of exoplanet host stars and draw two subsamples of > 200 systems with similar stellar parameters in regions of low and high stellar position-velocity clustering. After controlling for host star parameters, critically effective temperature, [M/H], and distance (but not age), we find little difference between the two populations’ exoplanet properties and populations. This demonstrates the importance of controlling for relationships between stellar and planet parameters. Note: Work submitted to Astronomy & Astrophysics (Received 5 June 2026) and soon to be published.