Asteroid Flyby

Monday, 12 July 2010 10:25

Comets/Meteors

ESA’s Rosetta mission has returned the first close-up images of the asteroid showing it is most probably a primitive survivor from the violent birth of the Solar System.

The flyby was a spectacular success with Rosetta performing faultlessly. Closest approach took place at 18:10 CEST, at a distance of 3162 km.

The images show that Lutetia is heavily cratered, having suffered many impacts during its 4.5 billion years of existence. As Rosetta drew close, a giant bowl-shaped depression stretching across much of the asteroid rotated into view. The images confirm that Lutetia is an elongated body, with its longest side around 130km.

The pictures come from Rosetta’s OSIRIS instrument, which combines a wide angle and a narrow angle camera. At closest approach, details down to a scale of 60 m can be seen over the entire surface of Lutetia.

"I think this is a very old object. Tonight we have seen a remnant of the Solar System’s creation," says Holger Sierks, OSIRIS principal investigator, Max Planck Institute for Solar System Research, Lindau, Germany.

Racing past an asteroid

Rosetta raced past the asteroid at 15 km/s completing the flyby in just a minute. But the cameras and other instruments had been working for hours and in some cases days beforehand, and will continue afterwards. Shortly after closest approach, Rosetta began transmitting data to Earth for processing.

Asteroid Lutetia

Lutetia has been a mystery for many years. Ground telescopes have shown that it presents confusing characteristics. In some respects it resembles a ‘C-type’ asteroid, a primitive body left over from the formation of the Solar System. In others, it looks like an ‘M-type’. These have been associated with iron meteorites, are usually reddish and thought to be fragments of the cores of much larger objects.

ESA News