September 13, 2013
Researchers Compile Virtual Atlas Of Asteroid Vesta
redOrbit Staff & Wire Reports - Your Universe Online
Astronomy enthusiasts can now take a virtual tour of the asteroid Vesta thanks to an atlas created from images captured during the Dawn Mission’s Low Altitude Mapping Orbit (LAMO), researchers announced Wednesday at the European Planetary Science Congress (EPSC) 2013 in London.The atlas, which was presented by Dr. Thomas Roatsch of the German Aerospace Center (DLR), was comprised of maps created from mosaics of 10,000 images from Dawn’s framing camera at an average altitude of approximately 130 miles.
There are 29 maps -- primarily at a scale of 1:200,000 -- featured in the atlas, the researchers explained. Those maps use three different projections: Mercator projections for equatorial regions, Lambert conical projections for mid-latitudes and a stereographic projection for the Rheasilvia basin at Vesta’s south pole.
“Creating the atlas has been a painstaking task – each map sheet of this series has used about 400 images,” Dr. Roatsch explained. “The atlas shows how extreme the terrain is on such a small body as Vesta. In the south pole projection alone, the Severina crater contours reach a depth of [11 miles]; just over [60 miles] away the mountain peak towers [4.3 miles] above the ellipsoid reference level.”
Since the LAMO mapping phase occurred during northern winter on Vesta, the north pole of the asteroid was completely dark, and the 30th tile of the region is blank, the authors said. There were also a few gaps in the LAMO coverage that had to be filled with lower-resolution images captured during the High Altitude Mapping Orbit (HAMO) phase, when the probe was located some 420 miles above the surface.
In addition to high-resolution map tiles, the downloadable atlas files also includes an index map, a perspective view and a color-coded and shaded relief map, Dr. Roatsch's team said. Contour lines were derived from a digital terrain model of the asteroid, and are reportedly based on a flattened ellipsoid 177 miles by 142 miles at its widest point. Also, for purposes of the atlas, Vesta’s prime meridian passes nearby the tiny crater Claudia, which measures approximately 2,000 feet in diameter and is located at 1.66°S and 356°E.
“All positions used by the Dawn project are in that Claudia system,” Europlanet, a network of planetary scientists, said in a statement. “The names of all geological features relate to Roman Vestals, famous Roman women, cities in which the cult of Vesta is known or festivals in which the Vestals participated. The nomenclature was proposed by the Dawn team and approved by the International Astronomical Union.”
During the same session at EPSC, researchers also presented the first complete version of the Vesta Atlas of Spectral Parameters. This atlas will allow researchers to infer data pertaining to the mineralogy of the surface of the asteroid, and represents a composite of all the observations made by the Visible and Infrared Mapping Spectrometer (VIR). A total of 84 digital maps were created with the same projection scheme used for the virtual atlas.