Ejecta exchange and satellite color evolution in the Pluto system, with implications for KBOs and asteroids with satellites

In this Note, I present first-order scaling calculations to examine the efficacy of impacts by Kuiper Belt debris in causing regolith exchange between objects in the Pluto system. It is found that ejecta can escape Nix and Hydra with sufficient velocity to reach one another, as well as Charon, and even Pluto. The degree of ejecta exchanged between Nix and Hydra is sufficient to cover these bodies with much more material than is required for photometrically change. In specific, Nix and Hydra may have exchanged as up to 10s of meters of regolith, and may have covered Charon to depths up to 14 cm with their ejecta. Pluto is likely unaffected by most Nix and Hydra ejecta by virtue of a combination of dynamical shielding from Charon and Pluto's own annual atmospheric frost deposition cycle. As a result of ejecta exchange between Nix, Hydra, and Charon, these bodies are expected to evolve their colors, albedos, and other photometric properties to be self similar. These are testable predictions of this model, as is the prediction that Nix and Hydra will have diameters near 50 km, owing to having a Charon-like albedo induced by ejecta exchange. As I discuss, this ejecta exchange process can also be effective in many KBOs and asteroids with satellites, and may be the reason that very many KBO and asteroid satellite systems have like colors.

[1]  Chadwick A. Trujillo,et al.  Properties of the Trans-Neptunian Belt: Statistics from the Canada-France-Hawaii Telescope Survey , 2001 .

[2]  Nicholas A. Peters,et al.  Counterfactual quantum computation through quantum interrogation , 2006, Nature.

[3]  W. Hartmann.  Impact experiments. I - Ejecta velocity distributions and related results from regolith targets , 1985 .

[4]  Elisabetta Pierazzo,et al.  A Reevaluation of Impact Melt Production , 1997 .

[5]  Marc W. Buie,et al.  Separate Lightcurves of Pluto and Charon , 1997 .

[6]  H. A. Weaver,et al.  The Positions, Colors, and Photometric Variability of Pluto's Small Satellites from HST Observations 2005-2006 , 2006 .

[7]  K. Holsapple.  THE SCALING OF IMPACT PROCESSES IN PLANETARY SCIENCES , 1993 .

[8]  S. Alan Stern,et al.  Why is Pluto bright? Implications of the albedo and lightcurve behavior of Pluto , 1988 .

[9]  M. W. Buie,et al.  Discovery of two new satellites of Pluto , 2006, Nature.

[10]  E. Young,et al.  Pluto and Charon , 2003 .

[11]  David J. Tholen,et al.  Masses of Nix and Hydra , 2007 .

[12]  David J. Tholen,et al.  Pluto and Charon , 1997 .

[13]  Daniel D. Durda,et al.  Collision Rates in the Present-Day Kuiper Belt and Centaur Regions: Applications to Surface Activation and Modification on Comets, Kuiper Belt Objects, Centaurs, and Pluto–Charon , 1999, astro-ph/9912400.

[14]  W. McKinnon,et al.  On the origin of the Pluto-Charon binary , 1989 .

[15]  S. Peale,et al.  Dynamics of the Pluto-Charon Binary , 1997 .

[16]  T. Loredo,et al.  Size Distribution of Multikilometer Transneptunian Objects , 2008 .

[17]  R. Canup,et al.  Forced Resonant Migration of Pluto's Outer Satellites by Charon , 2006, Science.

[18]  Dale P. Cruikshank,et al.  The solar system beyond Neptune , 2008 .

[19]  D. Strobel,et al.  N2 escape rates from Pluto's atmosphere , 2008 .

[20]  Jean-Luc Margot,et al.  Binaries in the Kuiper Belt , 2007, astro-ph/0703134.