'Bright spot' on dwarf planet has dimmer companion

Dwarf planet Ceres continues to puzzle scientists as a new image from NASA's Dawn spacecraft reveals that a bright spot that stands out in previous images lies close to yet another bright area.

Taken 46,000 kms from the dwarf planet, the "bright spot" can now be seen to have a companion of lesser brightness, but apparently in the same basin.

"This may be pointing to a volcano-like origin of the spots, but we will have to wait for better resolution before we can make such geologic interpretations," said Chris Russell, principal investigator for the Dawn mission based at the University of California, Los Angeles (UCLA).

Dawn is set to enter orbit around Ceres March 6.

The brightest spot continues to be too small to resolve with our camera, "but despite its size it is brighter than anything else on Ceres. This is truly unexpected and still a mystery to us," added Andreas Nathues, lead investigator from the Max Planck Institute for Solar System Research, Gottingen, Germany.

As scientists receive better and better views of the dwarf planet over the next 16 months, they hope to gain a deeper understanding of its origin and evolution by studying its surface.

Dawn visited the giant asteroid Vesta from 2011 to 2012, delivering more than 30,000 images of the body along with many other measurements, and providing insights about its composition and geological history.

Vesta has an average diameter of 525 kms while Ceres has an average diameter of 950 kms.

Vesta and Ceres are the two most massive bodies in the asteroid belt, located between Mars and Jupiter.