ESO’s Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument, installed on the Very Large Telescope at the Paranal Observatory in Chile, has taken unprecedented new images of 2 Pallas, 89 Julia, 29 Amphitrite and 324 Bamberga — four of the millions of rocky bodies in the main belt, a ring of asteroids between Mars and Jupiter.
Main-belt asteroids (clockwise from top left) 29 Amphitrite, 324 Bamberga, 2 Pallas, and 89 Julia. Image credit: Vernazza et al / ESO.
2 Pallas was discovered on March 28, 1802, by German astronomer Heinrich Wilhelm Matthäus Olbers.
The asteroid is approximately 318 miles (512) km wide. This makes it the third largest asteroid in the main belt and one of the biggest asteroids in the Solar System.
It contains about 7% of the mass of the entire asteroid belt — so hefty that it was once classified as a planet.
A third of the size of 2 Pallas, 89 Julia was discovered by French astronomer Édouard Stephan on August 6, 1866.
Its stony composition led to its classification as a silicaceous (S-type) asteroid.
Another S-type asteroid is a 143-mile- (230 km) wide body called 29 Amphitrite.
It was discovered by German astronomer Albert Marth on March 1, 1854, at the private South Villa Observatory in London, UK.
324 Bamberga was discovered even later: Austrian astronomer Johann Palisa found it on February 25, 1892.
With roughly the same diameter as 29 Amphitrite, 324 Bamberga is one of the largest carbonaceous (C-type) asteroids in the main belt.
Today, it is understood that C-type asteroids may actually be bodies from the outer Solar System following the migration of the giant planets. As such, they may contain ice in their interior.
Although the main belt is often portrayed in science fiction as a place of violent collisions, packed full of large rocks too dangerous for even the most skilled of space pilots to navigate, it is actually very sparse.
In total, the belt contains just 4% of the mass of the Moon, with about half of this mass contained in the four largest residents: Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea.
