The origin of (47171) Lempo-like Kuiper belt triple systems during binary-binary interactions

BRUNINI, ADRIÁN; LOPEZ, MARIA CRISTINA

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020

0035-8711

The trans-Neptunian triple Lempo-Paha-Hiisi is composed by atight inner binary with components of similar size, and an outer companionabout half their size, orbiting ten times further away. Large trans-Neptunianobjects like Pluto, also have multiple small moons, but Lempo´s structureis unique in the solar system, and the place and timing of its origin is stilla subject of debate. We propose a new formation mechanism able to forma large number of systems like Lempo-Paha-Hiisi, which involves binary-binary close encounters in the primordial planetesimal disk at 30 - 40 au.Some of these systems were then implanted in different populations of thetrans-Neptunian region during Neptune´s outward migration. Our resultsstrongly support that the 4:7 resonant multiple object Manwë-Thorondorwas once a triple system similar to Lempo-Paha-Hiisi, but the orbit of theinner binary evolved by tides, becoming a contact binary. As Lempo-Paha-Hiisi, its origin should have taken place in the planetesimal disk below 30 -40 au. Triple systems like Lempo-Paha-Hiisi or Manwë-Thorondor could nothave formed in situ and the existence of this kind of system is not expectedin the Cold Classical Kuiper Belt.