Global view of Vesta centered on the equator
Global view of Vesta centered on the equator
With diameters between 458 and 578 kilometres, asteroid Vesta, the third largest object in the asteroid belt, is not as irregularly shaped as most smaller asteroids – but it is not a sphere either. Since July 2011, NASA’s Dawn spacecraft has returned images of Vesta from a high-altitude orbit located 2420 kilometres above the asteroid’s surface, which are being used to produce image maps and shape models of this unique celestial body, as well as to determine its rotational axis and a system of latitude and longitude coordinates. The image resolution is about 250 metres per pixel.
Since Vesta’s axis is oblique, like that of the Earth, the asteroid experiences seasons. This is why the south pole of Vesta (bottom) is in full sunshine, whereas the high northern latitudes and the north pole are shaded and therefore invisible. Vesta’s surface is quite old, having formed more than 4.5 billion years ago. Many surface features, like the prominent band of troughs that stretch along the equatorial latitudes, are still mysterious to the scientists. High-resolution Dawn images from lower orbits, obtained late in 2011 might help answer questions regarding the geological evolution of this ‘embryonic planet’.
