Clifford Will

University of Florida, February 9, 12:00 pm

Adventures of a General Relativist in a Three-body World

The Newtonian three-body problem has a history that goes back to Newton, and continues to be relevant today. Following a brief history of the problem, we focus on hierarchical triple systems, in which an inner binary is perturbed by a distant body. This problem is amenable to a perturbative expansion in powers of the ratio of the two semimajor axes. We will review some of the remarkable phenomena that occur at various orders in the expansion, such as the famous Kozai-Lidov oscillations at quadrupole order and orbital flips at octupole order, and will discuss our own work to push the expansion to and beyond hexadecapole order. At dotriocontopole order, a new class of effects arises from the second-order interaction of quadrupole terms, affecting systems where the third body is much more massive than the inner binary. When GR corrections are introduced, additional effects occur, including suppression of Kozai-Lidov oscillations, and new contributions to Mercury’s perihelion advance, potentially detectable by the current Bepi-Colombo mission.