The formation of retrograde planetary orbits by close stellar encounters
Department of Astronomy, College of Liberal Arts and Sciences,
University of Florida 211 Bryant Space Science Center, Gainesville, FL
We consider the growing number of observations of the RossiterMcLaughlin eﬀect in transiting planets, which seem to suggest that ~30% of transiting planets are in highly inclined or retrograde orbits. We consider the dense cluster environment in which stars are born and investigate whether perturbations from passing stars can drive planetary systems into retrograde conﬁgurations. We ﬁnd that ﬂy-bys can result in signiﬁcantly more inclination excitation than might naively be expected from impulse approximations, leading to several percent of stellar systems possessing planets in retrograde orbits.
© Owned by the authors, published by EDP Sciences, 2011