* Astronomy

Researchers from the University of North Dakota and from the Max Planck Institute for Solar System Research in Germany have discovered a new kind of asteroid using NASA's Infrared Telescope Facility on Mauna Kea, Hawaii. The mineralogical composition of 1999 TA10 suggests that unlike many other asteroids it did not originate from the outer rocky crust of its parent asteroid Vesta, but from deeper layers. Until now, no asteroid with this composition was known. With the help of this new discovery it is now possible to determine the thickness of Vesta's crust and study its internal structure. In this summer Vesta will be the first destination of NASA's mission DAWN. In addition, the body with a diameter of approximately 525 kilometres is believed to be the only remaining protoplanet from the early phase of our solar system. (Icarus, in press, published online on December 5th, 2010)

The asteroid Vesta is unique: Unlike all other minor planets, that orbit the Sun within the main belt between the orbits of Mars and Jupiter, Vesta has a differentiated inner structure: A crust of cooled lava covers a rocky mantle and a core made of iron and nickel - quite similar to the terrestrial planets Mercury, Venus, Earth, and Mars. Scientists therefore believe this onion-like built asteroid to be a protoplanet, a relict from an early phase of planet formation more than four and half billion years ago. All other protoplanets either accumulated to form planets or broke apart due to violent collisions.