The US space probe Dawn has left the orbit of Vesta, one of the biggest asteroids in the solar system, and is headed for a rendezvous with the dwarf planet Ceres in February 2015, NASA said.

Dawn left behind Vesta at around 0626 GMT on September 5, after nearly a year spent circling the asteroid and mapping its previously uncharted surface, NASA said on its website.

"The findings are helping scientists unlock some of the secrets of how the solar system, including our own Earth, was formed," NASA said.

Vesta and Ceres are both located between Mars and Jupiter.

NASA's deep space network of antennas and communications facilities confirmed the spacecraft's departure from Vesta's orbit, the space agency said.

Launched September 27, 2007, Dawn is equipped with a high resolution camera and two spectrometers.

It weighs 1.2 tons and is 1.64 meters (5.3 feet) long and 1.27 meters (4.1 feet) wide, and is powered by an electric motor with ion propulsion that enables it to travel great distances at high speeds.

Discovered in 1801, Cereis is spherical body that is 960 kilometers (596 miles) in diameter and is made up of dense frozen water around a rocky core.

It was classified in 2006 as one of three "dwarf planets" in our solar system along with Pluto and Eris, under a new definition arrived at by the International Astronomical Union after it took away Pluto's status as a planet.

Vesta was discovered in 1807. It is a large, irregularly shaped rock, with an iron core and no trace of water. Its diameter is 520 kilometers (323 miles).

Dawn will travel a total of 5.1 billion kilometers (3.2 billion miles) on its $466 million mission.