Within Pluto’s informally named Vega Terra region is a field of eye-catching craters that looks like a cluster of bright halos scattered across a dark landscape.
The region is far west of the hemisphere NASA’s New Horizons spacecraft viewed during close approach last summer. The upper image – in black and white – sports several dozen “haloed” craters. The largest crater, at bottom-right, measures about 30 miles (50 kilometers) across. The craters’ bright walls and rims stand out from their dark floors and surrounding terrain, creating the “halo” effect.
In the lower image, composition data from New Horizons’ Ralph/Linear Etalon Imaging Spectral Array (LEISA) indicate a connection between the bright halos and distribution of methane ice, shown in false color as purple. The floors and terrain between craters show signs of water ice, colored in blue. Exactly why the bright methane ice settles on these crater rims and walls is a mystery; also puzzling is why this same effect doesn’t occur broadly across Pluto.
The upper view is a mosaic made from two separate images obtained by New Horizons’ Long Range Reconnaissance Imager (LORRI). A high-resolution strip taken at approximately 760 feet (232 meters) per pixel is overlain on a broader, low-resolution image taken at 2,910 feet (889 meters) per pixel. The images were obtained at ranges of 28,800 miles (46,400 kilometers) and 106,700 miles (171,700 kilometers) from Pluto, respectively, on July 14, 2015. The LEISA data came the same day, during the instrument’s highest-resolution scan of Pluto, with New Horizons 28,000 miles (45,500 kilometers) from Pluto, with a resolution of 1.7 miles (2.7 kilometers) per pixel.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
This week’s episode of NASA’s Space to Ground report on the Int. Space Station focuses on Bigelow Aerospace‘s BEAM habitat installed on the station last Saturday:
Craters with bright material on dwarf planet Ceres shine in new images from NASA’s Dawn mission.
Ceres’ Haulani Crater, with a diameter of 21 miles (34 kilometers), shows evidence of landslides from its crater rim. Smooth material and a central ridge stand out on its floor. This image was made using data from NASA’s Dawn spacecraft when it was in its high-altitude mapping orbit, at a distance of 915 miles (1,470 kilometers) from Ceres. This enhanced color view allows scientists to gain insight into materials and how they relate to surface morphology. Rays of bluish ejected material are prominent in this image. The color blue in such views has been associated with young features on Ceres. [Larger image]In its lowest-altitude mapping orbit, at a distance of 240 miles (385 kilometers) from Ceres, Dawn has provided scientists with spectacular views of the dwarf planet.
Haulani Crater, with a diameter of 21 miles (34 kilometers), shows evidence of landslides from its crater rim. Smooth material and a central ridge stand out on its floor. An enhanced false-color view allows scientists to gain insight into materials and how they relate to surface morphology. This image shows rays of bluish ejected material. The color blue in such views has been associated with young features on Ceres.
This image is from a mosaic of views that NASA’s Dawn spacecraft took in its low-altitude mapping orbit, at a distance of 240 miles (385 kilometers) from the surface of Ceres. In the center is Haulani Crater, which has a diameter of 21 miles (34 kilometers).“Haulani perfectly displays the properties we would expect from a fresh impact into the surface of Ceres. The crater floor is largely free of impacts, and it contrasts sharply in color from older parts of the surface,” said Martin Hoffmann, co-investigator on the Dawn framing camera team, based at the Max Planck Institute for Solar System Research, Göttingen, Germany.
The crater’s polygonal nature (meaning it resembles a shape made of straight lines) is noteworthy because most craters seen on other planetary bodies, including Earth, are nearly circular. The straight edges of some Cerean craters, including Haulani, result from pre-existing stress patterns and faults beneath the surface.
A hidden treasure on Ceres is the 6-mile-wide (10-kilometer-wide) Oxo Crater, which is the second-brightest feature on Ceres (only Occator’s central area is brighter). Oxo lies near the 0 degree meridian that defines the edge of many Ceres maps, making this small feature easy to overlook. Oxo is also unique because of the relatively large “slump” in its crater rim, where a mass of material has dropped below the surface. Dawn science team members are also examining the signatures of minerals on the crater floor, which appear different than elsewhere on Ceres.
The 6-mile-wide (10-kilometer-wide) crater named Oxo Crater is the second-brightest feature on Ceres. Only Occator’s central area is brighter. Oxo lies near the 0 degree meridian that defines the edge of many Ceres maps, making this small feature easy to overlook. NASA Dawn spacecraft took this image in its low-altitude mapping orbit, at a distance of 240 miles (385 kilometers) from the surface of Ceres. Oxo is also unique because of the relatively large “slump” in its crater rim, where a mass of material has dropped below the surface. Dawn science team members are also examining the signatures of minerals on the crater floor, which appear different than elsewhere on Ceres. The image has been rotated so that north on Ceres is up. [Larger image]“Little Oxo may be poised to make a big contribution to understanding the upper crust of Ceres,” said Chris Russell, principal investigator of the mission, based at the University of California, Los Angeles.
Dawn’s mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: dawn.jpl.nasa.gov/mission.
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