Colloquium: Dr. Michael J. GaffeyDr. Michael Gaffey Department of Space Studies University of North Dakota Grand Forks, Manitoba
Exploration of asteroid (4) Vesta by the DAWN Spacecraft
Asteroid (4) Vesta is the second largest body in the asteroid belt and is one of three largely intact planetesimals from the formation epoch of the inner solar system. Unlike the other two bodies, igneous rocks on the surface of Vesta clearly show that this body experienced a strong heating episode which produced extensive melting of its rocky material within the first few million years after the formation of the solar nebula and long before the formation of the terrestrial planets. Four decades ago, telescopic spectra linked Vesta to the basaltic meteorites, which are the most common type of igneous meteorites falling to Earth. The DAWN spacecraft orbited Vesta for more than a year collecting multispectral images, visible to mid-infrared spectra, and neutron & gamma ray spectra. Although Vesta was the best known asteroid prior to the arrival of DAWN, the mission produced a number of major surprises and has led to significant improvements in our understanding of processes in the early solar system (as well as a lot of pretty images).