A Wunda-full world? Carbon dioxide ice deposits on Umbriel and other moons of Uranus

Post contributed by Dr. Mike Sori, Lunar and Planetary Laboratory, University of Arizona

Uranus and its moons have only ever been visited by one spacecraft, Voyager 2, which flew by the system in 1986.  One of its large moons, Umbriel, was found to have a mysterious bright ring 80-km-wide inside a 131-km-diameter crater named Wunda.  Image 1 shows Umbriel and this annulus-shaped feature.

 

Image 1 blog post

Image 1: Voyager 2 image 1334U2-001 showing the Uranian moon Umbriel; note the bright ring inside the crater Wunda at top of the image (which is at Umbriel’s equator).

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Pit chains on Enceladus

Post contributed by Dr. Emily S. Martin, Research Fellow, Center for Earth and Planetary Studies, National Air & Space Museum, Smithsonian Institution.

Pit chains are linear assemblages of circular to elliptical pits and have been observed across the solar system. Pit chains have been found on Venus, Earth, Mars, Phobos, Eros, Gaspra, Ida, and Vesta. Across the solar system, pit chains may form through a variety of mechanisms including the collapse of lava tubes, karst, venting, extensional fracturing, or dilational faulting. Saturn’s tiny icy moon Enceladus is the first body of the outer solar system on which pit chains have been identified. Enceladus is only 50km in diameter and is best known for its warm south pole and its watery plume emanating from prominent ridges known as tiger stripes. The source of the plume is likely a global liquid water ocean beneath an icy shell.

Image1

Image 1: The morphology of pit chains across the solar system. a. Eros from NEAR. Image no. 135344864. b. Phobos. Image PIA10367. c. Albalonga Catena, Vesta. d. Venus. Right-look Magellan data near 13°S, 112°E. e. Kilauea Volcano, Hawaii centered at 19.3909°N 155.3076°W. Image taken 12/06/2014, acquired from Google Earth on 04/20/2016. f. Ida, modified from image PIA00332. g. Gaspra, modified from Galileo image PIA00332. h. Pit chains in north-eastern Iceland centered near 65.9902°N and 16.5301°W. Image taken on 7/27/2012, acquired from Google Earth 04/20/2016. i. Pit chains on Mars from the Mars Global Surveyor Mars Orbiter Camera, centered near 6.5398°S and 119.9703°W on the flank of Arsia Mons. Image PIA02874.

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Frozen Seas on Mars and Earth


Posted by
Dr. Matt Balme, Open University, UK. 

(Re-posted from IAG Image of the Month, October, 2007)

Elysium Planitia

Images of the ‘frozen sea’ on Mars (a,b) from the High Resolution Stereo Camera of the ESA Mars Express Mission, and pack-ice (c) in the terrestrial Antarctic.

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