Work

Stability mapping of the new Uranian moon S/2025 U1 with updated masses for Cordelia, Ophelia, and Cressida

Year: 2026

Type: article

Abstract: We investigate the dynamics of Uranus’s inner satellite system considering three recent updates: the inclusion of the new moon S/2025 U1; revised mass estimates for Cordelia, Ophelia, and Cressida; and updated zonal harmonic coefficients (J 2 , J 4 , and J 6 ). Using numerical integrations, mean-motion resonance analysis, and frequency map analysis (FMA), we explored their impact on orbital stability. For the first time, we analyzed the dynamics of the newly discovered moon S/2025 U1 and find that it follows a stable orbit, exhibiting smooth variations in its orbital elements over 250 000 years. Depending on the adopted radius, the gravitational influence of S/2025 U1 on the surrounding region is more compatible with a body of approximately 5–7 km in radius, producing diffusion maps associated with a regular orbital evolution. Furthermore, the case R = 7 km shows a reduction in the diffusion of neighboring satellites, suggesting a possible local stabilizing effect on the system’s orbital evolution. We also identified inner and outer regions of low diffusion around its orbit, suggesting that the dynamical environment is compatible with the survival of coorbital particles or additional small satellites. In contrast, very high radius values, particularly R = 20 km, tend to increase diffusion among neighboring satellites, making this scenario less compatible with a dynamically stable orbital configuration. We further explored the survival of hypothetical satellites near S/2025 U1. Our results show that bodies with masses up to 3× that of S/2025 U1 can remain stable in both the interior (between S/2025 U1 and Ophelia) and the exterior (between S/2025 U1 and Bianca) of its orbit. Finally, we find that the group formed by Cressida, Desdemona, Juliet, and Portia is the most sensitive to the updated parameters, showing noticeable changes in orbital stability and in the evolution of maximum eccentricity. While most mean-motion resonances among the satellites exhibit a circulating behavior, the 44:43 resonance between Belinda and Perdita acts as a confinement mechanism for the Belinda-Cupid-Perdita system, with a libration amplitude smaller than previously reported.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202558328

Authors: J. Xavier, A. Amarante, S. Giuliatti Winter, A. Ferreira

Institutions: Instituto Federal de Educação, Ciência e Tecnologia de Alagoas, Universidade Estadual Paulista (Unesp)

Language: English

Topic: Astro and Planetary Science

Subfield: Space and Planetary Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,865