Other
Scientific paper
Dec 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufm.p51c1425c&link_type=abstract
American Geophysical Union, Fall Meeting 2008, abstract #P51C-1425
Other
5430 Interiors (8147), 5450 Orbital And Rotational Dynamics (1221), 5475 Tectonics (8149), 6270 Pluto And Satellites
Scientific paper
The Pluto-Charon binary dwarf planet system is probably the result of an impact of similar-sized Kuiper Belt objects. The pair evolved from an unknown initial state to the dynamical end state in which we find them now, synchronously locked to each other. In this presentation, we investigate the implications of the evolution to this end state for the tidally-induced surface stresses on Pluto and Charon, and the interior state of Pluto. We predict that Pluto's tectonics are dominated by despinning stresses, and that Pluto had an internal ocean during the time that it was tectonically active. We assume that Charon rapidly despins post-impact to achieve synchronous rotation. The remaining orbital evolution is accomplished by transferring Pluto's spin angular momentum to Charon's orbit. The timescale over which the orbital evolution takes place is critically dependent on the tidal quality factor, Q, of Pluto. Previous investigators have assumed a constant Q = 100 for Pluto, but Q depends strongly on the internal structure. We have estimated the value of Q for layered viscoelastic Pluto interior structures at different tidal frequencies. The simplest (and perhaps least realistic) model is a homogeneous Pluto with uniform viscosity. In this model, the Pluto-Charon system will evolve to its current state within solar system history as long as the viscosity is less than 1019 Pa. A cold, stiff lid on Pluto's surface will lengthen the timescale of orbital evolution, and we are currently quantifying this effect. The most rapid orbital evolution occurs for an interior structure that is fully differentiated and contains a liquid water ocean decoupling the cold ice at the surface from a warm interior. If Pluto's interior ice begins relatively warm, our calculations show that tidal dissipation will add energy faster than convection can remove it, and internal melting is likely. Pluto may have had one of two fates after the Charon-forming impact: a cold interior which would not evolve to the current orbital state within solar system history, or a warmer interior which experiences a thermal runaway to produce an internal ocean. The orbital evolution of Pluto-Charon can produce hundreds of MPa of despinning stresses in Pluto's outer ice shell, and this is the largest source of surface stress. As long as the viscosity of Pluto's outer ice shell is 107 higher than the interior viscosity, these stresses will build up faster than they can viscously relax, and create fracturing on the surface that may be observed by New Horizons when it arrives at Pluto.
Barr Amy Courtright
Collins Geoffrey C.
No associations
LandOfFree
Tectonics and Interior Structure of Pluto: Predictions from the Orbital Evolution of the Pluto-Charon System does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Tectonics and Interior Structure of Pluto: Predictions from the Orbital Evolution of the Pluto-Charon System, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tectonics and Interior Structure of Pluto: Predictions from the Orbital Evolution of the Pluto-Charon System will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1239181