Saturn’s F ring
Current and previous work centered around creating and running numerical models of Saturn’s rings, making direct comparisons to Cassini data. Saturn’s rings are an ideal nearby location to study an astrophysical disk in real time by the in-situ space craft Cassini. Thus, we are able to test some of our theoretical ideas of planet and moon formation in this local laboratory. One of the most exciting and dynamic places in the Solar System is the narrow F ring at the edge of the main rings. Here a nearby moon Prometheus regularly and destructively interacts with the F ring.
The unique location (close to Saturn’s Roche Limit) and the destructive tendencies of moon closest moon lead to clumps and small moonlets being formed and destroyed on an hourly basis.
By comparing images taken by the Cassini spacecraft (a) orbiting Saturn with our models (b) we can start to understand some of the physics of what is happening. The density map from our models match very well with the changes in surface brightness seen in the real F ring. Essentially it shows that Prometheus is capable of significantly increasing the local density in the F ring in just a matter of hours.
Further analysis then shows that net rotations in the particle flow occur during such encounters. This can have important consequences for planet formation in larger disks were rotational flows or vortices are thought to overcome some shortfalls in planet formation time scales.
Recent advances in observational studies of exoplanets have begun to reveal some exciting yet dynamically challenging binary systems. In such systems it isn’t the exoplanets that might be of most interest when looking for life, but their moons due to the additional tidal energy delivered. Little is known about real Earth like moons around giant planets. Although limited studies have shown they can exist in stable habitable locations around their host stars and circumbinary host planets outside the normal habitable zone for the planet. However, if such exomoons can exist how do they form? Currently I am looking at creating a few models to investigate the dynamics of rings around some recently discovered circumbinary planets. The aim is to find answers as to whether exomoon formation is likely in-situ around circumbinary exoplanets.
Detecting Gravitational Waves With Planetary Rings
Gravitational waves oscillate in gravitational potential energy but pass through most matter completely unnoticed. However, orbital resonances can occur for very long wavelength gravitational waves with particles in planetary rings. The small amplitudes of these waves then become amplified in the orbits of ring particles. Work with Prof Feo Kusmartsev aims to show that gravitational waves can reveal themselves when passing through certain systems.