Finding the trigger to Iapetus' odd global albedo pattern: Dynamics of dust from Saturn's irregular satellites

  title={Finding the trigger to Iapetus' odd global albedo pattern: Dynamics of dust from Saturn's irregular satellites},
  author={Daniel Tamayo and Joseph A. Burns and Douglas P. Hamilton and Matthew M. Hedman},
Abstract The leading face of Saturn’s moon Iapetus, Cassini Regio, has an albedo only one tenth that on its trailing side. The origin of this enigmatic dichotomy has been debated for over 40 years, but with new data, a clearer picture is emerging. Motivated by Cassini radar and imaging observations, we investigate Soter’s model of dark exogenous dust striking an originally brighter Iapetus by modeling the dynamics of the dark dust from the ring of the exterior retrograde satellite Phoebe under… Expand
Iapetus’ near surface thermal emission modeled and constrained using Cassini RADAR Radiometer microwave observations
Abstract Since its arrival at Saturn, the Cassini spacecraft has had only a few opportunities to observe Iapetus, Saturn’s most distant regular satellite. These observations were all made from longExpand
Radial profiles of the Phoebe ring: A vast debris disk around Saturn
Abstract We present observations at optical wavelengths with the Cassini Spacecraft’s Imaging Science System of the Phoebe ring, a vast debris disk around Saturn that seems to be collisionallyExpand
Dust and Snow Cover on Saturn's Icy Moons
The final analysis of the Cassini radar observations of Saturn's icy moons presented here shows that the exchange of material between the planet's dust rings and moons, which is specific to theExpand
Infrared spectroscopic characterization of the low-albedo materials on Iapetus
Abstract Iapetus, one of the large satellites of Saturn, has been studied over the centuries for its signature brightness contrast, light on one side and dark on the opposite. It has recently beenExpand
Red material on the large moons of Uranus: Dust from the irregular satellites?
Abstract The large and tidally-locked “classical” moons of Uranus display longitudinal and planetocentric trends in their surface compositions. Spectrally red material has been detected primarily onExpand
Saturn's icy satellites investigated by Cassini-VIMS. IV. Daytime temperature maps
Abstract The spectral position of the 3.6 µm continuum peak measured on Cassini-VIMS I/F spectra is used as a marker to infer the temperature of the regolith particles covering the surfaces ofExpand
Small particles dominate Saturn’s Phoebe ring to surprisingly large distances
Saturn’s faint outermost ring, discovered in 2009 (ref. 1), is probably formed by particles ejected from the distant moon Phoebe. The ring was detected between distances of 128 and 207 Saturn radiiExpand
Direct imaging of irregular satellite discs in scattered light
Direct imaging surveys have found that long-period super-Jupiters are rare. By contrast, recent modeling of the widespread gaps in protoplanetary disks revealed by ALMA suggests an abundantExpand
Black rain: The burial of the Galilean satellites in irregular satellite debris
Abstract Irregular satellites are dormant comet-like bodies that reside on distant prograde and retrograde orbits around the giant planets. They are likely to be captured objects. Dynamical modelingExpand
Surface modification of icy satellites: Space weathering of the large moons of Uranus and alluvial fan formation on Saturn’s moon Titan
The surfaces of the large Uranian satellites are characterized by a mixture of H2O ice and a dark, potentially carbon-rich, constituent, along with CO2 ice. At the mean heliocentric distance of theExpand


Formation of Iapetus’ Extreme Albedo Dichotomy by Exogenically Triggered Thermal Ice Migration
It is demonstrated that all these characteristics, and the asymmetry’s large amplitude, can be plausibly explained by runaway global thermal migration of water ice, triggered by the deposition of dark material on the leading hemisphere. Expand
Iapetus: Unique Surface Properties and a Global Color Dichotomy from Cassini Imaging
Thermal migration of water ice explains the observed color asymmetry of Saturn’s unusual moon, Iapetus, and reveals a global color dichotomy, wherein both dark and bright materials on the leading side have a substantially redder color than the respective trailing-side materials. Expand
Probing the origin of the dark material on Iapetus
Among the icy satellites of Saturn, Iapetus shows a striking dichotomy between its leading and trailing hemispheres, the former being significantly darker than the latter. Thanks to the Visual andExpand
The sculpting of Jupiter’s gossamer rings by its shadow
Detailed modelling is presented that shows that the passage of ring particles through Jupiter’s shadow creates the Thebe extension and fully accounts for these Galileo results on dust impacts detected during the Galileo spacecraft's traversal of the outer ring region. Expand
The Contamination of Iapetus by Phoebe Dust
We examine whether the dark, orbitally-leading hemisphere of Saturn's satellite Iapetus might be coated by debris from low-albedo Phoebe, which orbits retrograde well exterior to Iapetus. UsingExpand
Compositional mapping of Saturn's satellite Dione with Cassini VIMS and implications of dark material in the Saturn system
Cassini VIMS has obtained spatially resolved imaging spectroscopy data on numerous satellites of Saturn. A very close fly-by of Dione provided key information for solving the riddle of the origin ofExpand
A new perspective on the irregular satellites of Saturn – II. Dynamical and physical origin
The origin of the irregular satellites of the giant planets has been long debated since their discovery. Their dynamical features argue against an in situ formation suggesting that they are capturedExpand
Imaging of Titan from the Cassini spacecraft
Observations of Titan from the imaging science experiment onboard the Cassini spacecraft reveal intricate surface albedo features that suggest aeolian, tectonic and fluvial processes, and imply that substantial surface modification has occurred over Titan's history. Expand
Dusty Rings and Circumplanetary Dust: Observations and Simple Physics
Each giant planet is encircled by planetary rings, usually composed of particles centimeters to meters in radius, but each system also contains regions where much smaller dust grains predominate.Expand
Iapetus’ geophysics : rotation rate, shape, and equatorial ridge
Iapetus has preserved evidence that constrains the modeling of its geophysical history from the time of its accretion until now. The evidence is (a) its present 79.33-day rotation or spin rate, (b)Expand