The geology and geophysics of Kuiper Belt object (486958) Arrokoth

The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, are primitive objects preserving information about Solar System formation. The New Horizons spacecraft flew past one of these objects, the 36 km long contact binary (486958) Arrokoth (2014 MU69), in January 2019. Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters diameter) within a radius of 8000 km, and 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

The CFEPS High Ecliptic Latitude Extension

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Systematic Biases In the Observed Distribution of Kuiper Belt Object Orbits

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On the Detection of Two New Transneptunian Binaries from the CFEPS Kuiper Belt Survey

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First extreme and far ultraviolet spectrum of a Comet Nucleus: Results from 67P/Churyumov-Gerasimenko

International audienceWe used the Alice spectrograph onboard the Rosetta comet orbiter spacecraft to observe the surface of comet 67P/Churyumov-Gerasimenko in the extreme and far ultraviolet (EUV/FUV) from 700-2050 Å in mid-August 2014. These observations were before significant EUV/FUV coma signatures were observed by Alice. The resulting coadded spectrum has high signal to noise and reveals: (1) a very FUV-dark surface with (2) a blue spectral slope and (3) no evidence of significant H2O ice absorption in the FUV. We fit the measured reflectance spectrum with a model including 99.5% tholins, 0.5% H2O-ice, and a neutral darkening agent. Since we could not find any natural material with sufficiently low EUV/FUV reflectance, we interpret the low I/F as evidence of a fluffy, light-trapping surface. We interpret the blue spectral slope as consistent with a surface consisting primarily of tholins, though it may alternatively be the result of Rayleigh scattering by fine particles in the regolith

The Canada-France Ecliptic Plane Survey (CFEPS) -High Latitude Component

We report the orbital distribution of the Trans-Neptunian objects (TNOs) discovered during the High Ecliptic Latitude (HiLat) extension of the Canada-France Ecliptic Plane Survey (CFEPS), conducted from June 2006 to July 2009. The HiLat component was designed to address one of the shortcomings of ecliptic surveys (like CFEPS), their lack of sensitivity to high-inclination objects. We searched 701 deg 2 of sky ranging from 12 • to 85 • ecliptic latitude and discovered 24 TNOs, with inclinations between 15 • to 104 •. This survey places a very strong constraint on the inclination distribution of the hot component of the classical Kuiper Belt, ruling out any possibility of a large intrinsic fraction of highly inclined orbits. Using the parameterization of Brown (2001), the HiLat sample combined with CFEPS imposes a width 14 • ≤ σ ≤ 15.5 • , with a best match for σ = 14.5 •. HiLat discovered the first retrograde TNO, 2008 KV 42 , with an almost polar orbit with inclination 104 • , and (418993), a scattering object with perihelion in the region of Saturn's influence, with a ∼ 400 AU and i = 68 •

The Canada-France ecliptic plane survey - first year data release: the orbital structure of the Kuiper belt

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