Water in Asteroids and Meteorites

Organisateurs : Humberto Campins (University of Central Florida, US), Antonella Barucci (LESIA)

The presence and distribution of water in asteroids is relevant to the origin and evolution of these objects, of our Solar System, and even of Earth’s own water. Water in asteroids has been detected in the form of hydrated minerals and recently as surface ice. The study of water and hydrated minerals in meteorites is equally exciting and relevant to this topic. A focused workshop that would bring together the astronomical and meteoritic communities would be a rare forum likely to advance significantly this field.
There have been important recent developments in this field. The tantalizing indication of water ice surviving in the Themis asteroid family, as suggested by the cometary activity observed in two asteroids belonging to this family, has been confirmed by the detection of surface ice on asteroid 24 Themis by two independent groups (Campins et al. 2010, Rivkin and Emery 2010). The presence of any ice on asteroid 24 Themis, particularly over a significant fraction of its surface, is puzzling because of the instability for exposed water ice at Themis’s heliocentric distance ( 3.2 AU). Nevertheless, there are several possible sources for this unstable ice and identifying them is likely to be diagnostic of important processes on primitive asteroids. The identification of the source of surface ice on this and other asteroids will be one of the main goals of this workshop. In addition, understanding the abundance of water in this region of the asteroid belt can constrain models of Solar System formation, and may also be related to the origin of Earth’s water and organic molecules. In fact, it has been suggested that the bulk of the water presently on Earth was carried by a few planetary embryos formed in the outer asteroid belt (Morbidelli et al. 2000).