Berlioz crater, in contrast to Kandinsky or Prokofiev located at higher latitudes, gets too hot even in the permanent shadow on its floor to have water ice on the surface. However, temperatures slightly below the surface are sufficiently cold for water ice to be stable. The image here provides a look at a crater that is suspected to host buried water ice.
The top image shows a view of Berlioz crater, with the regions that host radar-bright material (yellow) and persistent shadows (red) identified. The middle image was acquired a few hours after the top image, using a longer exposure of the WAC broadband filter, and stretched to reveal the details within the shadowed crater. A distinctively darker region is seen on the crater's floor, which corresponds well with the radar-bright and shadowed regions (bottom image). The darker, low-reflectance material is postulated to be composed of frozen, organic-rich, volatile materials that form through a lag deposit process . Read more about the recently published study using this image and others in this news story .
This image was acquired as part of MDIS's campaign to image within regions of permanent shadow in ice-bearing polar craters. Imaging with the WAC broadband clear filter, which has a bandwidth of 600 nanometers and is used for calibration imaging of stars, has the potential to reveal details of shadowed surfaces that are weakly illuminated by scattered sunlight. A variety of image exposure times and viewing conditions are employed to maximize the opportunity to resolve surface features of areas in permanent shadow.
June 23, 2013
Image Mission Elapsed Time (MET): 14301064, 14329855
Image ID: 4310618, 4312682
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 2 (700 nanometers)
Center Latitude of Middle Image: 78.81°
Center Longitude of Middle Image: 33.63° E
Scale: Berlioz crater (outlined in pink) has a diameter of 31 km (19 miles)
Projection: Polar stereographic about the north pole, with north to the top
Yellow Outline: Radar-bright regions , acquired by the Arecibo Observatory (Harmon et al, 2011, Icarus, 211, 37-50)
Red Outline: Region of persistent shadow
The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. During the first two years of orbital operations, MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.
For information regarding the use of images, see the MESSENGER image use policy .
|Mission||MESSENGER||National Astronomy and Ionosphere Center (NAIC)|
|Instrument Host||MESSENGER||Arecibo Observatory|
|Host Type||Orbiter||Ground-Based Observatory|
|Instrument||Mercury Dual Imaging System (MDIS)||Arecibo Radar|
|Detector||Wide Angle Camera (WAC)|
|Extra Keywords||Color, Crater, Radar, Radio, Shadow, Water|
|Date in Caption||2013-06-23|
|Image Credit||NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington|