The International Astronomical Union recently approved a new set of feature names for giant asteroid Vesta: Albia, Africana and Alypia Craters, to name a few. Among the features are dorsa (ridges), fossae (long, narrow shallow depressions), a rupes (scarp or cliff), and craters from Vesta’s mysterious north polar region. This compels us to take another close look at Vesta’s marvelous atlas.
An atlas of the asteroid Vesta, created from images taken during the Dawn mission’s low altitude mapping orbit (LAMO), is accessible for the public to explore online. The set of maps was created from mosaics of 10,000 images from Dawn’s framing camera (FC) instrument, taken at an altitude of about 210 kilometers. The maps are mostly at a scale of 1:200 0000 (1 centimeter = 2 kilometers), about that of regional road maps.
Creating the atlas was a painstaking task – each map sheet of this series used roughly 400 images. The atlas shows how extreme the terrain is on a body the size of Vesta. In the south pole projection alone, the Severina crater contours reach a depth of 18 kilometers; just over a hundred kilometers away the mountain peak towers 7 kilometers above the ellipsoid reference level.
The atlas comprises 29 maps using three different projections: Mercator for equatorial regions, Lambert conical projections for mid-latitudes, and a stereo-graphic projection for the Rheasilvia basin at Vesta’s south pole. Because the LAMO mapping phase took place during northern winter on Vesta, when the north pole was in complete darkness, the thirtieth tile of Vesta’s north pole is blank. A few gaps in the LAMO coverage were filled with lower resolution images taken during the second high altitude mapping orbit (HAMO2) at about 700 kilometers above the surface of Vesta.
As well as the high-resolution map tiles, each of the downloadable files for the atlas includes an index map, a perspective view, and a color-coded and shaded relief map. Contour lines have been derived from a digital terrain model of Vesta and are based on a flattened ellipsoid 285 kilometers by 229 kilometers at its widest point.
For the purposes of the atlas, Vesta’s prime meridian (zero degrees longitude) passes close to the tiny crater Claudia, measuring approximately 620 m in diameter, at 1.66°S and 356°E. All positions used by the Dawn project are in that Claudia system. 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.
Explore the Dawn mission’s Vesta Atlas Gallery!