Vesta's mineralogical composition as revealed by the visible and infrared spectrometer on Dawn
Article first published online: 8 JUL 2013
© The Meteoritical Society, 2013.
Meteoritics & Planetary Science
Volume 48, Issue 11, pages 2166–2184, November 2013
How to Cite
De Sanctis, M. C., Ammannito, E., Capria, M. T., Capaccioni, F., Combe, J.-P., Frigeri, A., Longobardo, A., Magni, G., Marchi, S., McCord, T. B., Palomba, E., Tosi, F., Zambon, F., Carraro, F., Fonte, S., Li, Y. J., McFadden, L. A., Mittlefehldt, D. W., Pieters, C. M., Jaumann, R., Stephan, K., Raymond, C. A. and Russell, C. T. (2013), Vesta's mineralogical composition as revealed by the visible and infrared spectrometer on Dawn. Meteoritics & Planetary Science, 48: 2166–2184. doi: 10.1111/maps.12138
- Issue published online: 16 DEC 2013
- Article first published online: 8 JUL 2013
- Manuscript Accepted: 2 MAY 2013
- Manuscript Received: 12 DEC 2012
- Italian Space Agency
- NASA's Dawn at Vesta Participating Scientists Program
The Dawn spacecraft mission has provided extensive new and detailed data on Vesta that confirm and strengthen the Vesta–howardite–eucrite–diogenite (HED) meteorite link and the concept that Vesta is differentiated, as derived from earlier telescopic observations. Here, we present results derived by newly calibrated spectra of Vesta. The comparison between data from the Dawn imaging spectrometer—VIR—and the different class of HED meteorites shows that average spectrum of Vesta resembles howardite spectra. Nevertheless, the Vesta spectra at high spatial resolution reveal variations in the distribution of HED-like mineralogies on the asteroid. The data have been used to derive HED distribution on Vesta, reported in Ammannito et al. (2013), and to compute the average Vestan spectra of the different HED lithologies, reported here. The spectra indicate that, not only are all the different HED lithologies present on Vesta, but also carbonaceous chondritic material, which constitutes the most abundant inclusion type found in howardites, is widespread. However, the hydration feature used to identify carbonaceous chondrite material varies significantly on Vesta, revealing different band shapes. The characteristic of these hydration features cannot be explained solely by infalling of carbonaceous chondrite meteorites and other possible origins must be considered. The relative proportion of HEDs on Vesta's surface is computed, and results show that most of the vestan surface is compatible with eucrite-rich howardites and/or cumulate or polymict eucrites. A very small percentage of surface is covered by diogenite, and basaltic eucrite terrains are relatively few compared with the abundance of basaltic eucrites in the HED suite. The largest abundance of diogenitic material is found in the Rheasilvia region, a deep basin, where it clearly occurs below a basaltic upper crust. However, diogenite is also found elsewhere; although the depth to diogenite is consistent with one magma ocean model, its lateral extent is not well constrained.