|Asteroids are considered the residual building blocks that formed the planets: a window to the formation and evolution of our solar system. Primitive asteroids (PAs) are characterized by dark surfaces dominated by carbon compounds and are associated to carbonaceous chondrites (CCs), the most pristine meteorites in our records. Both PAs and CCs are composed of water-bearing minerals and organics, and so they carry the answer to the unsolved question on how water and life appeared on Earth. These life-forming materials present rather featureless spectra in visible (VIS) and near-infrared wavelengths (0.5-2.5 μm). The most prominent feature in the VIS is the 0.7-μm band produced by hydrated silicates, which also produce an absorption band in the 3-μm region: whenever the 0.7-μm band is present, the 3-μm band is observed. However, this is not always true in the opposite way and so, the most diagnostic and reliable region to study hydrated mineralogies is the 3-μm region. In addition, many organic compounds present absorption bands in this region. Observing at these wavelengths is extremely complicated from ground-based telescopes due to Earth's atmosphere. Therefore, the 0.7-μm feature has been historically used as a proxy for hydration in PAs. The launch of the NASA James Webb Space Telescope in 2018 will change this point as its spectroscopic capabilities will allow detailed characterization of both organic and hydrated materials on the surface of asteroids at infrared wavelengths. Furthermore, there have been identified additional spectral features that might also be diagnostic of hydrated mineralogies and that need to be further explored, as is the case of a drop of reflectance below 0.5 μm or the 0.43-μm band associated to jarosite (hydrated silicate). These features appear in the region between ~0.35 and 0.5 μm, the "blue-visible" region (blue-VIS), and it will be covered by the ESA Gaia space telescope. Gaia will provide spectra for hundreds of thousands of asteroids in the 0.35-0.9 μm wavelength range.
The broad scientific objective of this project is do an exhaustive and systematic study of the hydrated mineralogies of primitive asteroids from the blue-VIS (0.35-μm) to the 3-μm region. We will extend our currently on-going PRIMitive Asteroids Spectroscopic Survey (PRIMASS) in the visible and near-infrared down to the blue-VIS (0.35 μm) to exploit the upcoming spectral data of thousands of primitive asteroids observed by Gaia, and up to the 3-μm with the use of the spectral data provided by the JWST. The final goal is to fully understand the hydrated mineralogies of the primitive asteroids and to map the primitive material in the asteroid belt. This will provide a general context for the interpretation of the science return from the two current space missions that are on their way to reach two primitive asteroids and return sample material from their surfaces.
This project studies the physical and compositional properties of the so-called minor bodies of the Solar System, that includes asteroids, icy objects, and comets. Of special interest are the trans-neptunian objects (TNOs), including those considered the most distant objects detected so far (Extreme-TNOs or ETNOs); the comets and the comet-asteroid