Want to stay on top of all the space news? Follow @universetoday on TwitterCeres is by far the largest and most massive asteroid in the belt between Mars and Jupiter. It is approximately the size of Texas or 975km x 909km with a mass of 9.5×1020. It actually represents one third of all of the mass of the asteroid belt. It has enough mass to achieve self gravity, which is a major requirement to be considered a dwarf planet. It is the smallest of the currently recognized dwarfs. It revolves around the sun every 1679.819 days with a very small axial tilt. The surface is relatively warm. The asteroid peak temperature is thought to be in the neighborhood of -38°C(235 K). Ceres has a visual brightness magnitude of +6.9 to +9. When it is at the brightest point possible, Ceres is nearly bright enough to be seen with the naked eye. It can be seen with binoculars whenever it is above the horizon on a completely dark night.
Asteroid Ceres was discovered on New Years Day in 1801 by Giuseppe Piazzi. Piazzi was a monk and astronomer in Sicily. He was also the founding director of the Palermo Astronomical Observatory. Ceres was discovered using the Titius-Bode Law that predicts the position of planets based on a mathematical equation of their distance from the Sun. This law predicted the position of Uranus and led to the false belief that Ceres was a planet.
The Dawn space mission is scheduled to visit Ceres in 2015 after stopping by Vesta in 2011. There had been some problems with Dawn’s ion propulsion system, but it was reignited on June 8, 2009. As of June 15, 2009, Dawn is only 801 days away from Vesta on its way to Ceres. This space mission hopes to be the first to orbit and observe two planetary bodies, making spaceflight history.
Ceres has gone through a lot of reclassifications over its known history. In the beginning it was thought to be the eight planet. That lasted a short 50 years. It was then relegated to asteroid status, until the new system of classification brought a little more prominence as a dwarf planet. Who knows what the new findings by the Dawn space mission will bring to the scientific community and how it will effect this storied dwarf.
Here on Universe Today we have a great article about the possibility of life on Ceres. Follow this link for a good article about Ceres. Astronomy Cast offers a good episode about another dwarf planet, Pluto, and what lies beyond.