Vesta's Oppia crater, many views from Dawn's VIR
Filed under pretty pictures, explaining image processing, explaining science, asteroids, asteroid 4 Vesta, Dawn, mineralogy and petrology, spectroscopy
Dawn's Visible and Infrared Imaging Spectrometer (VIR) can see in wavelengths ranging from ultraviolet to infrared, from 300 to 5000 nanometers. Here, one VIR image is displayed three different ways. The top image is composed of red (700 nanometers), green (550), and blue (440) images, approximating the colors that the human eye might see. The middle image is one slice from the longer-wavelength end of the spectrum, where the surface emits heat in the form of infrared radiation. Light colors correspond to the hottest temperatures and the dark colors correspond to the coldest temperatures. The bottom image is another RGB composite image in which bands from the visible and infrared were combined to enhance the differences in the composition of Vesta's surface. In the case of this bottom image different colors correspond to characteristics of the variable composition of the surface. For example, in the bottom image the green ejecta blanket of the crater on the right is very distinctive against the blue and red surface of the rest of Vesta. This ejecta blanket is much harder to identify in the other images.
NASA / JPL / UCLA / ASI / INAF / IASF / IFSI
Original image data dated on or about August 8, 2011