New Horizons Successfully Explores the Kuiper Belt object ‘Ultima Thule’

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
New Horizons came within about 3,500 kilometers of Ultima Thule at 6:33 a.m. on Jan. 1, zooming past the object at more than 51,000 kilometers per hour.
Scientists from NASA’s New Horizons mission [1], including three researchers from the Institut de Planétologie et Astrophysique de Grenoble (IPAG/OSUG, UGA/CNRS) [2], released the first detailed images of the most distant object ever explored (6.5 billions km from the Sun) — the Kuiper Belt object 2004 MU69, nicknamed Ultima Thule. Its remarkable appearance, unlike anything we’ve seen before, illuminates the processes that built the planets four and a half billion years ago.
The new images — taken from as close as 28,000 kilometers on approach — revealed Ultima Thule as a "contact binary," consisting of two connected spheres. End to end, the world measures 31 kilometers in length. The team has dubbed the larger sphere "Ultima" (19 kilometers across) and the smaller sphere "Thule" (14 kilometers across).

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Among the findings made by the mission science team in the first days after the flyby are:
- Initial data analysis has found no evidence of rings or satellites larger than 1.8 kilometer in diameter orbiting Ultima Thule.
- Data analysis has also not yet found any evidence of an atmosphere.
- The color of Ultima Thule matches the color of similar worlds in the Kuiper Belt, as determined by telescopic measurements.
- The two lobes of Ultima Thule — the first Kuiper Belt contact binary visited — are nearly identical in color. This matches what we know about binary systems which haven’t come into contact with each other, but rather orbit around a shared point of gravity.
- The New Horizons spacecraft will continue uploading images and other data in the days and months ahead, with much higher resolution images yet to come. Complete return of all science data will span over the next 20 months.
Live updates and links to mission information are available on http://pluto.jhuapl.edu and www.nasa.gov.
Updated on 21 January 2019
[1] The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, designed, built and operates the New Horizons spacecraft, and manages the mission for NASA’s Science Mission Directorate. The Southwest Research Institute, based in San Antonio, leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama.
[2] The IPAG team is composed of : Bernard Schmitt, Eric Quirico, Leila Gabasova