London Telegraph 
October 28, 2011
A potato-shaped asteroid observed last year by a European space probe may in fact be the ancient remains of a planet that never formed, astronomers said yesterday.
“This is the first object of this kind we have ever seen,” said Stephane Erard of the Paris Observatory. “For virtually the first time, we have found a witness to the formation of the planets.”
Three studies published in the US journal science reported the outcome of an encounter last year of the asteroid, 21 Lutetia, with Europe’s comet-chasing probe, Rosetta.
The scout turned an array of cameras, thermal and spectroscopic sensors on Lutetia as it raced through the asteroid belt between Mars and Jupiter.