The role of Mab as a source for theμring of Uranus

Abstract

Context. We previously analysed how the solar radiation force combined with the planetary oblateness changes the orbital evolution of a sample of dust particles located at the secondary ring system of Uranus. Both effects combined with the gravitational perturbations of the close satellites lead to the depletion of these dust particles through collisions on the surfaces of these satellites on a timescale of hundreds of years. Aims. In this work we investigate if the impacts of interplanetary dust particles (IDPs) onto Mab's surface can produce sufficient particles to replenish the μ ring population. Methods. We first analysed through numerical simulations the evolution of a sample of particles ejected from the surface of Mab and computed the lifetime of the grains when the effects of the solar radiation pressure and the planetary oblateness are taken into account. Then we estimated the mass production rate due to the impacts of IDPs following a previously established algorithm, and used this value to determine the time necessary to accumulate an amount of particles comparable with the mass of the μ ring. Results. Based on an estimate of the flux of interplanetary particles and on the surface properties of Mab it is expected that the satellite supplies material to the ring at a rate of ∼3 g/s. Meanwhile, our numerical model showed that the ejected particles are removed from the system through collisions with the satellite, and the mean lifetime of the grains may vary from 320 to 1500 years, depending on the radius of the particle. Conclusions. The time necessary to accumulate the mass of the μ ring via ejection from Mab is much shorter than the mean lifetime of the particles, and a stationary regime is not reached. If the ring is kept in a steady state, other effects such as the electromagnetic force and/or the existence of additional bodies may play a significant role in the dust balance, but the current lack of information about the environment renders modelling these effects unfeasible.

Production and fate of the G ring arc particles due to Aegaeon (Saturn LIII)

“…Through the simplified model presented in Sfair & Giuliatti Winter (2012) we compute the mass production rate (M + ) due to the impacts of projectiles directly onto the surface of the satellite as…”

“…and the mass of the dust can be calculated by (Sfair & Giuliatti Winter 2012) m =A arc 4 3 πρ r 2 r 1 r 3 dN…”

The science case for spacecraft exploration of the Uranian satellites: Candidate ocean worlds in an ice giant system

“…Cupid and Mab were discovered using the Hubble Space Telescope (Showalter & Lissauer 2006;De Pater et al 2006). Mab orbits within the outermost and dusty µ-ring (blue colored region in Figure 3), which might be sustained by material ejected from the surface of this tiny moon (Showalter & Lissauer 2006;De Pater et al 2006;Sfair & Winter 2012). Furthermore, µ-ring material could spiral inward and coat the leading hemisphere of Puck (French et al 2017), and perhaps it also spirals outward and mantles Miranda, possibly contributing to its substantial regolith cover (Cartwright et al 2020a,b).…”

Neptune’s ring arcs confined by coorbital satellites: dust orbital evolution through solar radiation

“…The mass rate production (M + ) created by this process depends on the flux of the impactors (F imp ), the target cross-section (S), and the ejecta yield (Y ). With these parameters the amount of dust produced is Sfair & Giuliatti Winter (2012) present a simple algorithm that allows the computation of the mass rate production of the dust particles by this process. To compute F imp it was assumed an isotropic flux of IDPs at Neptune's heliocentric distance of 1 × 10 −17 (km/m 2 /s) (Poppe 2016).…”

“…With all these assumptions, Figure 11 presents the mass production rate for different sizes of satellites. The grey area in Figure 11 comes from different values of the velocities assumed for the projectile: 2.3km/s and 3.0km/s (Sfair & Giuliatti Winter (2012) and Poppe (2016), respectively). The IDPs population in the outer Solar System is poorly constrained.…”