Three impact craters of different sizes, arranged in the shape of a snowman, make up one of the most striking features on Vesta. In this view the three 'snowballs' are upside down, so that the shadows make the features easily recognisable. North is to the lower right in the image, which has a resolution of 70 metres per pixel. The image is composed of many individual photographs taken during the high-altitude mapping orbit, at about 680 kilometres above Vesta's surface.The largest of the three craters, Marcia, has a diameter of 60 kilometres. The central crater, which is about 50 kilometres in diameter, is named Calpurnia, and the lower crater, named Minucia, has a diameter of about 22 kilometres. Marcia and Calpurnia are possibly the result of an impact by doublet asteroids, whereas Minucia was formed by a later impact.To derive the colour information, images acquired by the German camera system on the Dawn spacecraft in two near-infrared channels (917 nanometres and 749 nanometres) and an ultraviolet channel (438 nanometres) were combined to create what is referred to as a pseudo-true colour image. The true colours of the surface of Vesta appear somewhat different, but the subtle changes in material properties across the craters and impact ejecta can be detected. In both Marcia and Calpurnia, landslides can be seen; also, dark material has been exposed below the rim of Marcia.
As NASA’s Dawn spacecraft sent the first images of Vesta back to Earth in July 2011, scientists immediately noticed numerous troughs, as if carved with a gigantic plough. This image shows two troughs in the Divalia Fossa system, running parallel to the lower edge of the image. The majority of these troughs extend along the equator, but a second group – inclined with respect to the equator – have been identified in the northern hemisphere. These parallel trenches are usually several hundred kilometres long, up to 15 kilometres wide and more than one kilometre in depth. They are the result of two large asteroid impacts at the South Pole, demonstrating that impact events that occurred hundreds of kilometres apart caused shocks throughout Vesta and altered its surface.
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’.
This image shows the south pole of, the third largest object in the asteroid belt. When NASA’s Dawn spacecraft approached asteroid Vesta in mid 2011, the science team was particularly eager to see the first images of its south pole.Images the Hubble Space Telescope had collected years before with low resolution showed a depression of several hundred kilometres in diameter at the asteroids’ south pole, perhaps the result of a giant impact the asteroid experienced in its early history. The first images from the survey orbit of Dawn have confirmed that the circular depression is real. The images Dawn returned from its July and August survey orbit at 2420 kilometres altitude above the surface, have scientists discussing whether the circular structure dominating this image was caused by a collision with another asteroid, or by internal processes operating early in the asteroid’s history. Images in higher resolution from Dawn’s lower orbits might help answer that question.
A visitor from Earth would encounter a dramatic landscape at Vesta's south pole: cliffs several kilometres high, deep trenches and craters which have formed the southern tip of this fascinating protoplanet in the asteroid belt, and a mountain massif up to 15 kilometres high. For the scientists working on the Dawn mission, it is not yet clear how this wild landscape was formed – collisions with other asteroids contributed, but also the internal processes that played a role during the asteroid’s early formation phases. This diagonal view was derived from a global digital elevation model of the asteroid created from stereo image data obtained with the German Framing Camera on board NASA's Dawn space probe at an altitude of 2420 kilometres above Vesta's surface. The images, which were acquired during Dawn's observation orbit, have a resolution of about 250 metres per pixel.
In the centre of a depression several hundred kilometres in diameter, located in the south pole of asteroid Vesta, a mountain is rising approximately 15 kilometres above the base of that depression. This makes the mountain, which measures roughly 200 kilometres in diameter at its base, one of the highest elevations on all known bodies with solid surfaces in the Solar System. The image shows the unnamed mountain in profile against the darkness of space.The image has been obtained with the Framing Camera on NASA’s Dawn spacecraft from a distance of about 2420 kilometres. The image resolution is about 250 metres per pixel.
Location is everything! This truism is valid on Earth and of course also in space – and for objects in the Solar System – as well. So when NASA’s Dawn spacecraft arrived at Vesta, one of the first tasks was to determine the precise orientation of the asteroids rotation axis, and to define a prime meridian from which 360 degrees can be counted to the east or west. This image shows a tiny crater about 500 metres in diameter (arrow) – named Claudia by the Dawn science team – that defines Vesta’s prime meridian which runs from the asteroid’s north pole to its south pole.When German astronomer Heinrich Olbers discovered Vesta on 29 March 1807 from his private observatory in Bremen, Germany, he named the asteroid after the Roman goddess of home, hearth and family – Vesta. In ancient Rome the sacred fires in Vesta’s temples have been guarded by the Vestals, who reignited the fires every first day of March. Claudia, the daughter of the Roman consul at the time, Appius Claudius Pulcher (‘the beautiful’), was a virgin Vestal in Rome during her father’s reign in 143 BC.
From stereo images obtained with Dawn’s framing camera, scientists were able to produce a global shape model of asteroid Vesta. With diameters between 458 and 578 kilometres, Vesta is not a spherical body, so its surface topography is referenced to the theoretical surface of a three-axial ellipsoidal body with semi-major axes of 289 kilometres, 280 kilometres, and 229 kilometres, respectively. On Earth, we reference all topography to the spherical ‘surface’ of our global ocean level. The image shows the elevation of surface structures above or below this ellipsoidal body with a horizontal resolution of about 750 metres per pixel.The terrain model of Vesta’s southern hemisphere shows a remarkable circular structure with a diameter of about 500 kilometres, its rim rising above the interior of the structure for more than 15 kilometres. From low-resolution images of the Hubble Space Telescope it was known that a big depression existed at Vesta’s south pole, and was suspected to be a big impact basin. Dawn scientists are investigating the processes that formed this structure.
The surface of asteroid Vesta, imaged by NASA’s Dawn spacecraft from an altitude of about 2400 kilometres, gives dramatic insights into the geology of this celestial body. Abundant impact craters reveal the violent youth experienced by the asteroid. By counting craters on distinct geological surface units scientists can deduce the relative ages of the asteroid’s surface. 3D vistas offer an opportunity to learn more about the morphology of craters on asteroids and the physical properties of the target material on Vesta’s surface.Use red-cyan (red-blue, or red-green) glasses to view the surface in three-dimensions. Image resolution is about 250 metres per pixel.
When NASA’s Dawn spacecraft sent the first images of asteroid Vesta, scientists were fascinated by an enormous mound inside a big circular depression at the south pole. From stereo images, recorded from an altitude of about 2400 kilometres, it was possible to compose 3D images showing the structure of the mountain, displayed in the right half of this anaglyph image. The base of the mountain has a diameter of about 200 kilometres, and its altitude above the surroundings is about 15 kilometres. The area around the peak of the mountain shows landslides recording downslope movement of material from the flanks of the mountain. Also visible are tectonic structures from the extension of Vesta’s crust.Use red-cyan (red-blue, or red-green) glasses to have a three-dimensional impression of the image. Image resolution is about 250 metres per pixel.
3D images have great potential for scientists to get a realistic impression of the solid surface of a planet. In this image, obtained by NASA’s Dawn spacecraft from an altitude of about 2400 kilometres above the surface of asteroid Vesta, an undulated topography with impact craters, ridges and grooves is visible in the area surrounding Vesta’s south pole.Use red-cyan (red-blue, or red-green) glasses for a three-dimensional impression of the image. Image resolution is about 250 metres per pixel.
This is the first global map of asteroid Vesta, composed from images recorded by the framing camera onboard NASA’s Dawn spacecraft. Since July 2011, Dawn has been orbiting the third largest object in the asteroid belt in a survey orbit of approximately 2400 kilometres above the surface, obtaining individual images with the camera’s clear filter with an image resolution of about 250 metres per pixel. The orbit will be progressively lowered so the global mosaic can be improved step by step in terms of resolution.The equator runs parallel to the upper image border, approximately above the bright, smooth band of troughs. Towards the north pole (top of image), a black, shadowed landscape indicates that Vesta’s northern latitudes are in seasonal shadow due to the northern polar ‘winter’ night lasting through the second half of 2011.Vesta is an irregular shaped body with semi-major axes measuring 289 kilometres, 280 kilometres, and 229 kilometres, respectively. The map is displayed in a geometry called ‘simple cylindrical projection’; in such a projection, the south pole point is stretched to a line the same length as the equator, forming the lower limit of the image; features in high southern latitudes appear distorted. Image resolution is 750 metres per pixel.
This image mosaic of Vesta’s south pole has been generated from dozens of individual images obtained with the framing camera onboard NASA’s Dawn spacecraft. The images have been recorded from an altitude of about 2400 kilometres above the asteroid’s surface.The image map is centered on the asteroid’s south pole, which is surrounded by several large impact craters with diameters of 20 to 50 kilometres. The mosaic is displayed in a stereographic projection; image resolution is 750 metres per pixel. The outer edge of the circular map corresponds to a latitude of 50 degrees south.