Color and Albedo Heterogeneity of Vesta from Dawn

<jats:title>A New Dawn</jats:title> <jats:p> Since 17 July 2011, NASA's spacecraft Dawn has been orbiting the asteroid Vesta—the second most massive and the third largest asteroid in the solar system (see the cover). <jats:bold> Russell <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="684" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1219381">684</jats:related-article> ) use Dawn's observations to confirm that Vesta is a small differentiated planetary body with an inner core, and represents a surviving proto-planet from the earliest epoch of solar system formation; Vesta is also confirmed as the source of the howardite-eucrite-diogenite (HED) meteorites. <jats:bold> Jaumann <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="687" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1219122">687</jats:related-article> ) report on the asteroid's overall geometry and topography, based on global surface mapping. Vesta's surface is dominated by numerous impact craters and large troughs around the equatorial region. <jats:bold> Marchi <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="690" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1218757">690</jats:related-article> ) report on Vesta's complex cratering history and constrain the age of some of its major regions based on crater counts. <jats:bold> Schenk <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="694" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1223272">694</jats:related-article> ) describe two giant impact basins located at the asteroid's south pole. Both basins are young and excavated enough amounts of material to form the Vestoids—a group of asteroids with a composition similar to that of Vesta—and HED meteorites. <jats:bold> De Sanctis <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="697" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1219270">697</jats:related-article> ) present the mineralogical characterization of Vesta, based on data obtained by Dawn's visual and infrared spectrometer, revealing that this asteroid underwent a complex magmatic evolution that led to a differentiated crust and mantle. The global color variations detailed by <jats:bold> Reddy <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="700" related-article-type="in-this-issue" vol="336" xlink:href="10.1126/science.1219088">700</jats:related-article> ) are unlike those of any other asteroid observed so far and are also indicative of a preserved, differentiated proto-planet. </jats:p>