Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 338 (6104), 242-6

Elemental Mapping by Dawn Reveals Exogenic H in Vesta's Regolith


Elemental Mapping by Dawn Reveals Exogenic H in Vesta's Regolith

Thomas H Prettyman et al. Science.


Using Dawn's Gamma Ray and Neutron Detector, we tested models of Vesta's evolution based on studies of howardite, eucrite, and diogenite (HED) meteorites. Global Fe/O and Fe/Si ratios are consistent with HED compositions. Neutron measurements confirm that a thick, diogenitic lower crust is exposed in the Rheasilvia basin, which is consistent with global magmatic differentiation. Vesta's regolith contains substantial amounts of hydrogen. The highest hydrogen concentrations coincide with older, low-albedo regions near the equator, where water ice is unstable. The young, Rheasilvia basin contains the lowest concentrations. These observations are consistent with gradual accumulation of hydrogen by infall of carbonaceous chondrites--observed as clasts in some howardites--and subsequent removal or burial of this material by large impacts.

Comment in

Similar articles

See all similar articles

Cited by 8 PubMed Central articles

See all "Cited by" articles

Publication types

LinkOut - more resources