As NASA's Dawn spacecraft closes in on the dwarf planet known as Ceres, it continues to show mission managers things they were not expecting.

According to a NASA news release, Dawn delivered images of the dwarf planet in the asteroid belt between Mars and Jupiter from about 29,000 miles away. The last images revealed Ceres' mysterious white spot had a similar, dimmer companion.

Dawn is expected to enter Ceres' orbit on March 6 and will be able to deliver images with even better resolution for a duration of about 16 months.

"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," Andreas Nathues, lead investigator for the framing camera team at the Max Planck Institute for Solar System Research, Gottingen, Germany, said in the release. "This is truly unexpected and still a mystery to us."

In 2011 and 2012, Dawn previously delivered about 30,000 images of Vesta, which accompanied by Ceres are the largest two objects in the asteroid belt.

"Ceres' bright spot can now be seen to have a companion of lesser brightness, but apparently in the same basin," Chris Russell, principal investigator for the Dawn mission, which is based at the University of California, Los Angeles, said in the release. "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."