Using a Statistical Accretion Model to Predict the Existence of Undetected Moons around Uranus in the Vicinity of Mab
Abstract
Showalter and Lissauer announced the discovery of an outer ring system around Uranus, in 2006. An accompanying small moon Mab was also detected (Showalter and Lissauer, 2006). They derived its orbital position from both Voyager flyby (1986) and HST (2003-2006) data and showed that its orbit is poorly understood. They compared the observed positions with an orbital model that includes gravitational flattening of Uranus. Although this model works well for nine other Uranian moons, for Mab the fitting errors of the observed orbital motion are six times larger. This indicates that we are currently overlooking an essential part of the dynamics that determine the orbit of Mab. They also demonstrated that the known Uranian moons do not serve as a source of the perturbation of its orbit. Are there undetected bodies in the Uranian system that affect Mab's orbit?
In this study, we applied a statistical accretion model (SAM) (Laskar, 2000) to determine the presence of undetected moons in the vicinity of Mab. We used a modified version of the model, including different aggregation criteria and employing conservation of total angular momentum (Mena and Benet, 2010). This model has been primarily used to simulate the evolution of the solar system, in the secular limit. Chaotic motion is promoted through the use of a Brownian motion mechanism. We incorporated an additional simple resonance mechanism to determine interaction with Mab. We also addressed challenges associated with applying this model to a thin, near-circular disc. We used the results of the SAM to run time-integration simulations, to analyze whether the actual effect of the accreted moons can be used to elucidate Mab's peculiar motion. We present preliminary results indicating the likely number of bodies in the neighbourhood of Mab, based on known observations of the variation of its orbit.- Publication:
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AAS/Division of Dynamical Astronomy Meeting #41
- Pub Date:
- May 2010
- Bibcode:
- 2010DDA....41.0806K