NASA’s Dawn spacecraft, which has been exploring the 330-mile wide asteroid Vesta since 2011, is continuing to reveal new details about the giant space rock and its geology. The findings, presented today at the European Geosciences Union meeting in Vienna, Austria, will help researchers better understand the processes that led to the formation of our solar system.
Images taken from varying distances above Vesta’s surface reveal new details about its composition, internal structure, and dramatic temperature changes taking place on the asteroid’s surface. Much of the materials seen by Dawn are rich in iron and magnesium minerals, which are found on Earth in volcanic rock. Researchers also see breccias, which are rocks fused during impacts from space debris. Images also reveal what is described as “smooth pond-like deposits”, which scientists believe may be the result of fine dust settling in low lying regions after impact events.
“Dawn now enables us to study the variety of rock mixtures making up Vesta’s surface in great detail,” said Harald Hiesinger, a Dawn participating scientist at Münster University in Germany. “The images suggest an amazing variety of processes that paint Vesta’s surface.”
At the asteroid’s south pole, in an area known as the Tarpeia crater, researchers have identified bands of minerals that appear as layers on the crater’s steep slopes. Layers at the surface reveal signs of contamination from impact events, while layers under Vesta’s surface preserve more of the giant asteroid’s original characteristics. Possible landslides on the Tarpeia crater’s slopes also reveal other hidden mineral patterns, which is strong evidence to show that Vesta’s surface is constantly changing and renewing.
Dawn has also mapped Vesta’s surface temperatures in the highest resolution of any asteroid to date, and data reveals temperatures varying from as warm as -10 degrees Fahrenheit in the sunniest spots to -150 degrees Fahrenheit in the shadows. It’s very likely that it gets even colder, because Dawn cannot measure temperatures on the surface lower than -150 degrees Fahrenheit.
“After more than nine months at Vesta, Dawn’s suite of instruments has enabled us to peel back the layers of mystery that have surrounded this giant asteroid since humankind first saw it as just a bright spot in the night sky,” said Carol Raymond, Dawn deputy principal investigator at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. “We are closing in on the giant asteroid’s secrets.”
For more information about NASA’s Dawn mission exploring the asteroid Vesta, please visit www.nasa.gov/dawn