Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt object.

S A Stern,D C Richardson,D J Mccomas,J C Cook,M S Lahr,A J Steffl,S J Robbins,M Simon,B Carcich,H A Weaver,L S Glaze,I R Linscott,M P Conner,D E Kaufmann,D C Schurr,T H Zurbuchen,K N Singer,K D Runyon,J J Kavelaars,G K Oxton,S M Krimigis,A Harch,H K Kang,M E Hill,W M Grundy,M Pätzold,C J Bierson,A H Parker,E Bernardoni,A M Zangari,O S Custodio,L S Turner,M E Summers,E W Stahlheber,P Kollmann,C B Olkin,R A Beyer,J E Lee,J Eisig,F Scipioni,T Stryk,M W Buie,M C Kochte,O M Umurhan,D J Rodgers,M Hahn,T Andert,D P Cruikshank,R M Tedford,M K Bird,A M Earle,W M Owen,V J Bray,A Hosadurga,W B Mckinnon,H A Elliott,D Velez,H M Hart,M H Versteeg,M M Stothoff,G R Gladstone,G P Keleher,C B Beddingfield,H B Throop,J T Keane,H J Reitsema,M R Showalter,D W Hals,J M Freeze,W M Folkner,D F Strobel,R W Webbert,A F Egan,D J Katz,B J Buratti,E Quirico,J Firer,M Horányi,L E Brown,M E Banks,H W Taylor,M A Ritterbush,S Bhaskaran,C J A Howett,S B Porter,A D Howard,O L White,F Bagenal,B L Enke,C M Lisse,M G Ryschkewitsch,R L Mcnutt,D T Britt,S Protopapa,D J Schultz,L A Young,J R Spencer,J Van Eck,M N Fosbury,Fréderic Pelletier ,Jeffrey M Moore ,Carrie L Chavez ,Cristina M Dalle Ore ,M R El‐Maarry ,Bernard Schmitt ,Allen Lunsford ,Dennis C Reuter ,Donald E Jennings ,David Aguilar ,Leila Gabasova ,Declan Mages ,Dylan Boone ,Gerhard Kruizinga ,Jason D Hofgartner ,Jeffrey Stuart ,Joseph E Riedel ,Kristen Harmon ,A Cheng ,Alice Bowman ,Alysen Regiec ,Brian Bauer ,Carl J Ercol ,Carl S Engelbrecht ,Christopher B Hersman ,Christopher C Deboy ,David Y Kusnierkiewicz ,Doug Mehoke ,Edwin J Colwell ,Gabe Rogers ,Gabrielle Griffith ,George Lawrence ,Glen H Fountain ,Helene Winters ,Hien D Nguyen ,J R Hayes ,J.r Jensen ,Jorge Núñez ,Joshua Albers ,K Beißer ,Karl Whittenburg ,Katie Bechtold ,Laura M Burke ,Magda Saina ,Mark E Holdridge ,Melissa R Jones ,Merry Buckley ,Neda Behrooz ,Paul E Rosendall ,Priya Dharmavaram ,Rebecca Sepan ,Richard Shelton ,S A Cooper ,S Jaskulek ,Sarah A Hamilton ,Stephen Williams ,Steven J Conard ,Stewart S Bushman ,T Adrian Hill ,Thomas Mehoke ,Valerie Mallder ,Wayne Schlei ,Yanping Guo ,Tod R Lauer ,P Schenk ,Richard P Binzel ,M J Kinczyk ,Susan Benecchi ,S Weidner ,N Martin ,Chelsea L Ferrell ,Cindy Conrad ,Debi Rose ,Emma Birath ,J Redfern ,J W Parker ,John P Andrews ,Michael A Vincent ,Tiffany J Finley ,E Fattig ,G Dunn ,J Hanley ,J Scherrer ,Mark B Tapley ,J Stansberry ,Jon P Pineau ,M Piquette ,Rajani D Dhingra ,Douglas P Hamilton ,A Verbiscer ,Brian Harold May ,Gerald Weigle ,A Chaikin ,Anthony H Taylor ,Bobby G Williams ,Dale Stanbridge ,Derek Nelson ,Erik J Lessac-Chenen ,J Bauman ,Joel T Fischetti ,John Pelgrift ,Kenneth E Williams ,Michael J Salinas ,A Ocampo ,James Green ,Joanna Wendel

doi:10.1126/science.aaw9771

Abstract

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.

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