2025/02/26 by Zhihao Fu, Hongping Deng, D. N. C. Lin +1 · 1 voice
Physics and Astronomy · #Astrophysics and Star Formation Studies #Astro and Planetary Science #Stellar, planetary, and galactic studies
paper · pdf · doi:10.1126/sciadv.adu6058
openalex publication_date 2025/02/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/15
The origin of planetary mass objects (PMOs) wandering in young star clusters remains enigmatic, especially when they come in pairs. They could represent the lowest-mass object formed via molecular cloud collapse or high-mass planets ejected from their host stars. However, neither theory fully accounts for their abundance and multiplicity. Here, we show via hydrodynamic simulations that free-floating PMOs have a unique formation channel via the fragmentation of tidal bridges between encountering circumstellar disks. This process can be highly productive in dense clusters like Trapezium forming metal-poor PMOs with disks. Free-floating multiple PMOs also naturally emerge when neighboring PMOs are caught by their mutual gravity. PMOs may thus form a distinct population that is fundamentally different from stars and planets.