| Literature DB >> 32054695 |
W B McKinnon1, D C Richardson2, J C Marohnic2, J T Keane3, W M Grundy4,5, D P Hamilton2, D Nesvorný6, O M Umurhan7,8, T R Lauer9, K N Singer6, S A Stern6, H A Weaver10, J R Spencer11, M W Buie6, J M Moore7, J J Kavelaars11, C M Lisse10, X Mao12, A H Parker6, S B Porter6, M R Showalter8, C B Olkin6, D P Cruikshank7, H A Elliott13,14, G R Gladstone13, J Wm Parker6, A J Verbiscer15, L A Young6.
Abstract
The New Horizons spacecraft's encounter with the cold classical Kuiper Belt object (486958) Arrokoth (provisional designation 2014 MU69) revealed a contact-binary planetesimal. We investigated how Arrokoth formed and found that it is the product of a gentle, low-speed merger in the early Solar System. Its two lenticular lobes suggest low-velocity accumulation of numerous smaller planetesimals within a gravitationally collapsing cloud of solid particles. The geometric alignment of the lobes indicates that they were a co-orbiting binary that experienced angular momentum loss and subsequent merger, possibly because of dynamical friction and collisions within the cloud or later gas drag. Arrokoth's contact-binary shape was preserved by the benign dynamical and collisional environment of the cold classical Kuiper Belt and therefore informs the accretion processes that operated in the early Solar System.Entities:
Year: 2020 PMID： 32054695 DOI： 10.1126/science.aay6620
Source DB: PubMed Journal: Science ISSN： 0036-8075 Impact factor: 47.728