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

Science ◽  
2019 ◽  
Vol 364 (6441) ◽  
pp. eaaw9771 ◽  
Author(s):  
S. A. Stern ◽  
H. A. Weaver ◽  
J. R. Spencer ◽  
C. B. Olkin ◽  
G. R. Gladstone ◽  
...  

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.

Science ◽  
2020 ◽  
Vol 367 (6481) ◽  
pp. eaay6620 ◽  
Author(s):  
W. B. McKinnon ◽  
D. C. Richardson ◽  
J. C. Marohnic ◽  
J. T. Keane ◽  
W. M. Grundy ◽  
...  

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.


Science ◽  
2020 ◽  
Vol 367 (6481) ◽  
pp. eaay3999 ◽  
Author(s):  
J. R. Spencer ◽  
S. A. Stern ◽  
J. M. Moore ◽  
H. A. Weaver ◽  
K. N. Singer ◽  
...  

The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU69). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers. Arrokoth has a lightly cratered, smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.


Icarus ◽  
2021 ◽  
Vol 356 ◽  
pp. 113723 ◽  
Author(s):  
Jason D. Hofgartner ◽  
Bonnie J. Buratti ◽  
Susan D. Benecchi ◽  
Ross A. Beyer ◽  
Andrew Cheng ◽  
...  

2020 ◽  
Vol 496 (4) ◽  
pp. 4154-4173 ◽  
Author(s):  
A Amarante ◽  
O C Winter

ABSTRACT The New Horizons space probe led the first close flyby of one of the most primordial and distant objects left over from the formation of the Solar system, the contact binary Kuiper Belt object (486958) Arrokoth. This is composed of two progenitors, the lobes called Ultima and Thule. In the current work, we investigate Arrokoth’s surface in detail to identify the location of equilibrium points and also we explore each lobe’s individual dynamic features. We assume that Arrokoth’s irregular shape is a homogeneous polyhedra contact binary. We explore its dynamic characteristics numerically by computing its irregular binary geopotential in order to study its quantities, such as geometric height, oblateness, ellipticity and zero-power curves. The stability of Arrokoth Hill was also explored through zero-velocity curves. Arrokoth’s external equilibrium points have no radial symmetry due to its highly irregular shape. We identified even equilibrium points concerning its shape and spin rate: i.e. four unstable external equilibrium points and three inner equilibrium points, where two points are linearly stable, with an unstable central point that has a slight offset from its centroid. Moreover, the large and small lobes each have five equilibrium points with different topological structures from those found in Arrokoth. Our results also indicate that the equatorial region of Arrokoth’s lobes is an unstable area due to the high rotation period, while its polar locations are stable resting sites for surface particles. Finally, the zero-power curves indicate the locations around Arrokoth where massless particles experience enhancing and receding orbital energy.


2018 ◽  
Vol 45 (16) ◽  
pp. 8111-8120 ◽  
Author(s):  
Jeffrey M. Moore ◽  
William B. McKinnon ◽  
Dale P. Cruikshank ◽  
G. Randall Gladstone ◽  
John R. Spencer ◽  
...  

Life ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 126
Author(s):  
Dale P. Cruikshank ◽  
Yvonne J. Pendleton ◽  
William M. Grundy

The close encounters of the Pluto–Charon system and the Kuiper Belt object Arrokoth (formerly 2014 MU69) by NASA’s New Horizons spacecraft in 2015 and 2019, respectively, have given new perspectives on the most distant planetary bodies yet explored. These bodies are key indicators of the composition, chemistry, and dynamics of the outer regions of the Solar System’s nascent environment. Pluto and Charon reveal characteristics of the largest Kuiper Belt objects formed in the dynamically evolving solar nebula inward of ~30 AU, while the much smaller Arrokoth is a largely undisturbed relic of accretion at ~45 AU. The surfaces of Pluto and Charon are covered with volatile and refractory ices and organic components, and have been shaped by geological activity. On Pluto, N2, CO and CH4 are exchanged between the atmosphere and surface as gaseous and condensed phases on diurnal, seasonal and longer timescales, while Charon’s surface is primarily inert H2O ice with an ammoniated component and a polar region colored with a macromolecular organic deposit. Arrokoth is revealed as a fused binary body in a relatively benign space environment where it originated and has remained for the age of the Solar System. Its surface is a mix of CH3OH ice, a red-orange pigment of presumed complex organic material, and possibly other undetected components.


Author(s):  
S. Alan Stern ◽  
John R. Spencer ◽  
Anne Verbiscer ◽  
Heather E. Elliott ◽  
Simon P. Porter

Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Jenessa Duncombe

The flyby of Ultima Thule on New Year’s Day will give us our first glimpse of a mysterious Kuiper Belt object.


Nature ◽  
1993 ◽  
Vol 362 (6422) ◽  
pp. 730-732 ◽  
Author(s):  
David Jewitt ◽  
Jane Luu

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