4 Vesta or Vesta – the fourth in order of discovery of the asteroid from the asteroid belt orbiting between Mars and Jupiter.
Asteroid 4 Vesta was discovered by German astronomer Heinrich Wilhelm Olbers March 29, 1807 year in Bremen. The name comes from the asteroid goddess of the hearth of the mythology of Rome – Vesta.
Vesta asteroid’s orbit is tilted at an angle of 7.13 ° to the ecliptic, and its eccentricity is 0.09. It circulates in the body of an average distance of 2.36 me around the Sun, which needs 3 years and 230 days. It is the largest representative of the family asteroid Vesta.
Westy sizes are 560 × 578 × 458 km, so it is an object of irregular shape. Albedo of Vesta is relatively large compared to other such objects, and is 0.423. Maximum brightness, which it can achieve, is 5.5 meters. It is absolute magnitude and reaches 3.2 meters.
Vesta is the second largest asteroid of the main belt (after 1 Ceres), its mass is estimated to be 2.71 × 10 20 kg, while the average density of 3.4 g / cm 3. This asteroid is spinning quite rapidly around its axis – in one rotation needs 5 hours, 20 minutes and 31 seconds.
Vesta is probably similar to the construction of the Earth group planets and has an iron core surrounded by a shell. The shell is composed mostly of basalt. The surface of this asteroid bears the traces of numerous collisions with other bodies, even very large. There are there impact craters with diameters up to 150 km, the frozen streams of lava, which could escape from the shell shock as a result of other objects or activities of the volcanic, but which ceased billions of years ago.
The largest crater on the surface of Vesta, which could be observed by the Hubble Space Telescope, is a swimming pool Impact Rheasilvia with a diameter of about 460 km, with a distinct central elevation. The shafts of the crater have a height of 4 to 12 km above the surrounding terrain and is located in the center mountain has a height of 23 km from the base (there are about three times higher than Earth’s Mount Everest ).
The research spectroscopic shows that on the surface of Vesta is not enough minerals containing water and hydroxides.
4 Vesta is also a likely source of origin of some falling on Earth of meteorites called achodndrytami, which broke away from her as a result of numerous collisions with other asteroids.
27 September 2007 NASA sent in the direction of Vesta and Ceres spacecraft Dawn. July 16, 2011 around 05:00 UTC on the initial probe entered orbit around Vesta. In August, Dawn spacecraft launched study asteroids, which will last until July 2012. During this time artificial satellite probed. Later, the probe will be in the direction of Ceres.
This is the first in the history of the probe which entered orbit of the object in the main asteroid belt.