Institute of Astronomy

The stability of multiplanet systems on the Main Sequence and post-Main Sequence

SpeakerTalk DateTalk Series
Alexander Mustill28 July 2014Across HR 2014 Talks


When stars leave the main sequence they lose a significant fraction of their mass: around 50% for a Solar-mass star, and greater fractions for more massive stars. This mass loss has significant effects on the orbits of planets: in particular, in multi-planet systems, dynamical interactions become stronger, and previously stable systems can be destabilised. We study the stability of multi-planet systems through the lifetimes of their host stars, from the zero-age main sequence to an old white dwarf, with numerical integrations incorporating the changes to the star's mass and radius as it evolves. We show that orbital instability occurs following mass loss in many systems, both those that already experienced instability on the main sequence and those that were stable. We discuss implications for the orbits and detectability of giant planets orbiting WDs, the prospects for the delivery of terrestrial planets to the WD ""habitable zone"", and the efficiency of WD atmospheric pollution by destabilised planetesimals.