By Nadia Drake
THE WOODLANDS, Texas — The enormous asteroid Vesta is more like a small, rocky planet than other space rocks wandering around the asteroid belt between Mars and Jupiter. Among other planetlike characteristics, Vesta’s interior is probably divided into layers like Earth’s — and scientists have detected traces of an ancient magnetic field.
“We have a hard time working on this body and not thinking about it as a planet,” said UCLA’s Christopher Russell, principal investigator of the Dawn spacecraft that has been buzzing around Vesta since July.
Like Earth, Vesta probably has an iron core, a mantle and crust. Scientists don’t know how thick the crust is, but Dawn measurements suggest that the core’s radius is between 107 and 113 kilometers, Carol Raymond of the Jet Propulsion Laboratory said on March 22 at the Lunar and Planetary Science Conference. Vesta is only about 530 kilometers across, meaning that the core occupies almost half its diameter. And new gravity maps from Dawn reveal anomalies in the crust, or areas where there’s “likely mantle material close to the surface,” Raymond reported.