Institute of Astronomy

Dynamical evolution of eccentric planets and debris discs

SpeakerTalk DateTalk Series
Tim Pearce28 July 2014Across HR 2014 Posters


We examine the dynamical evolution of a single planet and a debris disc of equal or lower mass, if the planet is on an eccentric orbit bringing it close to or within the disc. An example of this scenario could be the aftermath of a planet – planet scattering event. By running a large suite of n-body integrations and combining these with theoretical results, we characterise the general evolution of such a system for a wide range of initial conditions. We find that there are two possible outcomes if the planet is more massive than the disc; either the inner region of the disc is removed and the remaining debris becomes eccentric and apsidally aligned with the planet, or the entire disc is ejected. In both cases the planet’s orbital elements undergo only minor changes, and we provide criteria to predict which of these outcomes will occur. We also find that if the planet and disc are of comparable mass then the former may undergo significant eccentricity damping and migration, and that the disc appearance differs considerably from the previous case. The overall shapes of both sets of discs and the density variations within them are characterised, as are the important timescales. The evolution of the planet’s orbit is also quantified in both cases. The results of this study may be used to predict the general outcomes of such a scenario, or to infer the properties of an unseen eccentric planet from features observed in debris discs.