A recent study investigates the formation of Oort cloud-like structures and interstellar comets within dense stellar environments. Most stars are born in areas where close encounters are frequent, significantly influencing the initial layout of their planetary systems. The solar system, with its extensive collection of distant comets, serves as an effective natural laboratory for examining these phenomena.
The research utilizes advanced numerical simulations through the LonelyPlanets framework, which integrates NBODY6++GPU and REBOUND. This approach aims to analyze the evolution of debris disks surrounding solar system analogs situated in stellar clusters. The study considers two initial configurations: an Extended model and a Compact model, each composed of four giant planets alongside either an extended or compact debris disk.
Findings indicate that compact disks predominantly generate populations resembling the Kuiper Belt and scattered disk through interactions with the planet-disk dynamics. In contrast, extended disks are significantly influenced by stellar encounters, leading to the formation of structures akin to the Oort cloud and interstellar comets with ejection velocities ranging from 1 to 3 km/s.
The effectiveness of stellar perturbations is notably high for encounter inclinations between 0 degrees and 30 degrees, resulting in distinct dynamical populations, including Sednoids and inner Oort cloud analogs, as well as a recognizable tail within semi-major axis-eccentricity space. During coplanar encounters, the disk maintains a largely flattened structure; however, polar flybys result in a vertical redistribution of angular momentum, creating nearly isotropic outer populations that mirror an emerging Oort cloud.
The implications of this research suggest that the reservoirs of comets and interstellar objects are natural outcomes of interactions between planets and debris disks, alongside stellar flybys occurring in densely populated clusters. This connects the design of outer planetary systems to the environments in which they originated.
The study, authored by Santiago Torres, spans 19 pages and features 15 figures. It is currently under review at the journal Astronomy & Astrophysics.
