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Post Info TOPIC: Pluto-Charon ring


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Pluto-Charon system dust
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Title: Search for signatures of dust in the Pluto-Charon system using Herschel/PACS observations
Author: Gabor Marton, Csaba Kiss, Zoltan Balog, Emmanuel Lellouch, Erika Verebelyi, Ulrich Klaas

In this letter we explore the environment of Pluto and Charon in the far infrared with the main aim to identify the signs of any possible dust ring, should it exist in the system. Our study is based on observations performed at 70 um with the PACS instrument onboard the Herschel Space Observatory at 9 epochs between March 14 and 19, 2012. The far-infrared images of the Pluto-Charon system are compared to those of the point spread function (PSF) reference quasar 3C454.3. The deviation between the observed Pluto-Charon and reference PSFs are less then 1 sigma indicating that clear evidence for an extended dust ring around the system was not found. Our method is capable of detecting a hypothetical ring with a total flux of ~3.3 mJy at a distance of ~153 000 km (~8.2 Pluto-Charon distances) from the system barycentre. We place upper limits on the total disk mass and on the column density in a reasonable disk configuration and analyse the hazard during the flyby of NASAs New Horizons in July 2015. This realistic model configuration predicts a column density of 8.7x10^(-10) gcm^(-2) along the path of the probe and an impactor mass of 8.7x10^(-5) g.

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Posts: 130044
Date:
Pluto-Charon ring
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Title: Evolution of a ring around the Pluto-Charon binary
Author: B. C. Bromley, S. J. Kenyon

We consider the formation of satellites around the Pluto-Charon binary. An early collision between the two partners likely produced the binary and a narrow ring of debris, out of which arose the moons -- Styx, Nix, Kerberos and Hydra. Yet how the satellites emerged from the compact ring is uncertain. Here we show that a particle ring can spread from physical collisions and collective gravitational scattering, similar to migration. Around a binary, these processes take place in the reference frames of `most circular' orbits, akin to circular ones in a Keplerian potential. Ring particles can damp to these orbits, avoiding destructive collisions. Damping and diffusion can also help particles survive dynamical instabilities driven by resonances with the binary. In some situations, particles get trapped near resonances that sweep outward with the tidal evolution of the Pluto-Charon binary. With simple models and numerical experiments, we show how the Pluto-Charon impact ring may have expanded into a broad disk, out of which grew the circumbinary moons. In some scenarios, the ring can spread well beyond the orbit of Hydra, the most distant moon, to form a handful of smaller satellites. If these small moons exist, New Horizons will find them.

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