Sublimating Iapetus? |
Sublimating Iapetus? |
Sep 30 2008, 11:55 AM
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#1
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Junior Member Group: Members Posts: 57 Joined: 21-September 06 Member No.: 1172 |
Two interesting reports were submitted this year to EGU'08 and DPS'08 conferences, "Magnetic signature of Iapetus’ interaction with the solar wind" and "Iapetus Is An Obstacle To The Solar Wind".
Abstract: QUOTE In September 2007 the Cassini spacecraft flew by Iapetus while the moon was in the solar wind, upstream of Saturn. The spacecraft approached from downstream and to the side, but did not pass through the moon's geometric wake. As Cassini reached a point where the interplanetary magnetic field would have connected the spacecraft to Iapetus, the magnetometer observed a strong, and unexpected, perturbation about the diameter of the moon in size. When mapped towards the moon, the perturbation rotates the magnetic field to avoid Iapetus. This perturbation was unlike other variations in the solar wind. Using a three-dimensional simulation of the solar wind-Iapetus interaction, we find that Cassini was too far from the moon to observe the signature due to an inert body. Two familiar sources of perturbations near planetary bodies are mass loading (ionization of neutral gas) and magnetization. Recent work has postulated that Iapetus loses material from the surface via sublimation, but no direct observations of this process have been made. The Earth’s Moon and Mars have crustal magnetization, but Jupiter’s Ganymede is the only non-planetary body confirmed to have a global magnetic field strong enough to deflect the surrounding plasma flow. We use the observations and results from simulation to explore the possibility of and place limits on any mass loading or magnetization at Iapetus. What kind of material can be sublimating there? Maybe Cassini found a sign for iapetusian activity, geysers or something? |
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Sep 30 2008, 02:06 PM
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#2
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Senior Member Group: Members Posts: 1887 Joined: 20-November 04 From: Iowa Member No.: 110 |
QUOTE Recent work has postulated that Iapetus loses material from the surface via sublimation They are probably referring to the explanation for the dark terrain on Iapetus' trailing side. During the long daylight hours some of the more volatile light material around the edges of the dark terrain sublimates leaving the dark material behind as a deposit. This allows the dark areas on the trailing side to expand slowly. |
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