The formation of celestial bodies like the Oort Cloud and interstellar comets in dense stellar environments is a captivating yet complex topic in astrobiology. Most stars are born in these crowded stellar nurseries, where close encounters can dramatically alter the early development of planetary systems.
The solar system, with its vast collection of distant comets, serves as a natural laboratory for studying these processes. In this research, we delve into the evolution of debris disks around solar system analogues nestled within stellar clusters, employing advanced numerical simulations. We explore two distinct initial configurations: an Extended model and a Compact model, each featuring four giant planets and either an extended or compact debris disk.
Our findings reveal that compact disks primarily give rise to Kuiper belt and scattered disk-like populations through intricate planet-disk interactions. Conversely, extended disks are significantly shaped by stellar encounters, resulting in the formation of Oort cloud-like structures and interstellar comets with ejection velocities ranging from 1 to 3 km/s. Stellar perturbations are most effective for encounter inclinations between 0° and 30°, leading to the emergence of unique dynamical populations, such as Sednoids and inner Oort cloud analogues, along with a distinctive tail in the semi-major axis-eccentricity space.
In coplanar encounters, the disk maintains its flattened structure, while polar flybys redistribute angular momentum vertically, producing nearly isotropic outer populations that bear a resemblance to the emerging Oort cloud. These results suggest that cometary reservoirs and interstellar objects are natural outcomes of planet-disk interactions and stellar flybys in dense clusters, establishing a connection between the architecture of outer planetary systems and their birth environments.
This research, authored by Santiago Torres, is currently under review at the prestigious journal A&A, and it invites further exploration and discussion within the scientific community. The full paper, comprising 19 pages and 15 figures, can be accessed via the arXiv preprint server. The study is categorized under the subjects of Earth and Planetary Astrophysics, Astrophysics of Galaxies, and Solar and Stellar Astrophysics, and it can be cited using the provided DOI: 10.48550/arXiv.2510.23653.
