Science News

Asteroid vesta has a homogenous interior

New Delhi: Scientists have used the radiometric data from NASA’s Deep Space Network and imaging by the Dawn spacecraft, that orbited the asteroid between 16 July 2011 and 5 September 2012, and discovered that the asteroid Vesta has a more homogenous internal structure than previously believed, with either a very small iron core or no core at all. The researchers mapped minute fluctuations in the gravitational field of the body in space, and measured the wobble of the asteroid as it spun, which is sensitive to the internal structure.

As a spinning skater pulls in outstretched arms, the spin speeds up because of the movement of the center of gravity and a decrease in inertia. By carefully measuring the inertia of Vesta, the scientists could determine the internal structure. A differentiated interior would mean a concentration of mass towards the core, and a low inertia, but a higher inertia would indicate that the mass was evenly distributed. The research challenges the conventional understanding of Vesta, which was previously believed to be a protoplanet that survived the chaotic infancy of the Solar System.

4 Vesta

Vesta is one of the earliest asteroids discovered, and is the second-most massive object in the main belt between Mars and Jupiter, after Ceres. Vesta measures 525 kilometres across, and scientists believed that it once had a solid crust and a liquid mantle, allowing for the heavier elements to sink deeper and form a metallic core. The asteroid was battered by other asteroids, and could not regain its spherical shape. As such, Vesta is an object that bridges the mass gap between an asteroid and a planet. The surface is covered in basaltic rock, indicating a volcanic past, something that is a rarity among asteroids. The same innovative technique was also used to produce the most detailed map so far of the interior of the Moon.