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

2020 ◽  
Vol 499 (3) ◽  
pp. 4206-4212
Author(s):  
Adrián Brunini ◽  
María Cristina López

ABSTRACT The trans-Neptunian triple Lempo–Paha–Hiisi is composed of a tight inner binary with components of similar size and an outer companion about half their size orbiting 10 times further away. Large trans-Neptunian objects like Pluto also have multiple small moons, but Lempo’s structure is unique in the Solar system, and the place and timing of its origin is still a subject of debate. We propose a new formation mechanism able to form a large number of systems like Lempo–Paha–Hiisi, which involves binary–binary close encounters in the primordial planetesimal disc at 30–40 au. Some of these systems were then implanted in different populations of the trans-Neptunian region during Neptune’s outward migration. Our results strongly support that the 4:7 resonant multiple object Manwë–Thorondor was once a triple system similar to Lempo–Paha–Hiisi, but the orbit of the inner binary evolved by tides, becoming a contact binary. As with Lempo–Paha–Hiisi, it should have originated in the planetesimal disc below 30–40 au. Triple systems like Lempo–Paha–Hiisi or Manwë–Thorondor could not have formed in situ and the existence of this kind of system is not expected in the cold classical Kuiper belt.

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.


Author(s):  
D.E. Brownlee ◽  
A.L. Albee

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.


2016 ◽  
Vol 10 (3) ◽  
pp. 259-270
Author(s):  
Ludmila Matienko ◽  
◽  
Larisa Mosolova ◽  
Vladimir Binyukov ◽  
Gennady Zaikov ◽  
...  

Mechanism of catalysis with binary and triple catalytic systems based on redox inactive metal (lithium) compound {LiSt+L2} and {LiSt+L2+PhOH} (L2=DMF or HMPA), in the selective ethylbenzene oxidation by dioxygen into -phenylethyl hydroperoxide is researched. The results are compared with catalysis by nickel-lithium triple system {NiII(acac)2+LiSt+PhOH} in selective ethylbenzene oxidation to PEH. The role of H-bonding in mechanism of catalysis is discussed. The possibility of the stable supramolecular nanostructures formation on the basis of triple systems, {LiSt+L2+PhOH}, due to intermolecular H-bonds, is researched with the AFM method.


Author(s):  
O. Mousis ◽  
D. H. Atkinson ◽  
R. Ambrosi ◽  
S. Atreya ◽  
D. Banfield ◽  
...  

AbstractRemote sensing observations suffer significant limitations when used to study the bulk atmospheric composition of the giant planets of our Solar System. This impacts our knowledge of the formation of these planets and the physics of their atmospheres. A remarkable example of the superiority of in situ probe measurements was illustrated by the exploration of Jupiter, where key measurements such as the determination of the noble gases’ abundances and the precise measurement of the helium mixing ratio were only made available through in situ measurements by the Galileo probe. Here we describe the main scientific goals to be addressed by the future in situ exploration of Saturn, Uranus, and Neptune, placing the Galileo probe exploration of Jupiter in a broader context. An atmospheric entry probe targeting the 10-bar level would yield insight into two broad themes: i) the formation history of the giant planets and that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. An atmospheric probe could represent a significant ESA contribution to a future NASA New Frontiers or flagship mission to be launched toward Saturn, Uranus, and/or Neptune.


Nanoscale ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 150-162
Author(s):  
Ezgi Onur Şahin ◽  
Harun Tüysüz ◽  
Candace K. Chan ◽  
Gun-hee Moon ◽  
Yitao Dai ◽  
...  

The formation mechanism of amorphous tantalum oxides was studied by total scattering experiments starting from alkoxide precursors. Hydrolysed TaxOyHz clusters form in highly dilute solutions which were transformed into L-Ta2O5 by calcination.


2002 ◽  
Vol 12 ◽  
pp. 214-218
Author(s):  
A. Brunini ◽  
M.D. Melita

AbstractA set of self-consistent simulations of the formation of Uranus and Neptune are performed to study the evolution of the native KBOs in the process. Our main goal is to have a deeper understanding of the impact of the formation of the outer planets on the present orbital structure of the trans-neptunian region. We aim to understand if resonance capture driven by the outward migration of Neptune can actually occur and its interplay with the invasion of massive planetesimals expelled from the Uranus-Neptune region as a byproduct of their formation. Also the putative present existence in the Oort reservoir of a population of objects originated in the Kuiper belt is analyzed.


2012 ◽  
Vol 14 (9) ◽  
pp. 2983 ◽  
Author(s):  
Hiroyuki Asakura ◽  
Kentaro Teramura ◽  
Tetsuya Shishido ◽  
Tsunehiro Tanaka ◽  
Ning Yan ◽  
...  

1998 ◽  
Vol 11 (2) ◽  
pp. 1155-1156
Author(s):  
H.U. Keller

Comets, the most pristine members of our solar system, are faint at large heliocentric distances (rh > 3 au) and therefore difficult to observe. Data reduction of these faint objects (periodic comets) is time consuming and hence most often just preliminary results can be discussed. Only the orbits of short periodic comets can be predicted and most of those that have been accessible for ISO have been covered within the guaranteed time programme. About 10 proposals were accepted by the selection for open time proposals. A target of opportunity team was formed. The outstanding comet Hale-Bopp (C/1995 01), one of the brightest and therefore most active comets of this century, was suggested and accepted as TOO. The important results from the ISO cometary programme are derived from its observations. In addition to the observations of "classic" comets the newly detected (Jewitt and Luu, 1993) transneptunian objects, probably objects from the Kuiper belt, are observed in an attempt to determine their physical properties.


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