Experts present new findings during a recent conference

May 11, 2012 07:07 GMT  ·  By
Image showing the mineral distribution in the southern hemisphere of the giant asteroid Vesta
   Image showing the mineral distribution in the southern hemisphere of the giant asteroid Vesta

At a conference held on Thursday, May 10, at the NASA Headquarters James E. Webb Auditorium, in Washington DC, experts presented the latest results obtained by the Dawn spacecraft. The mission is currently orbiting Vesta, the largest asteroid in our solar system.

At the meeting, scientists from numerous institutions spoke about the studies their respective organizations conducted based on data acquired by the orbiter. The spacecraft arrived at the asteroid in July 2011, and was originally supposed to depart on July 2012.

Since then, a 40-day mission extension has been allotted, and Dawn is continuing to study the surface and interior of the asteroid from its low orbit. Thanks to the orbiter, scientists have recently presented new data on how the object was produced early on in the solar system's history.

In addition, the findings also place the relationships between structures such as Vesta – believed to be a protoplanet – and small, rocky worlds, such as Mercury, Venus, Earth and Mars. The asteroid may have grown to be the fifth rocky planet, but something prevented it from growing.

The new studies reveal that the asteroid is in fact a fossil of the early solar system. It contains a remarkable degree of geological diversity, a finding that suggests that the protoplanetary disk from which all planets, asteroids and meteorites formed was a lot more chemically-diverse than originally thought.

Details of the new investigation were published in the May 10 issue of the top journal Science. One of the main conclusions is that Vesta more closely resembles the Moon or a dwarf planet than a common asteroid. This finding has important implications for understanding the evolution of the Sun.

“Dawn's visit to Vesta has confirmed our broad theories of this giant asteroid's history, while helping to fill in details it would have been impossible to know from afar,” Carol Raymond said yesterday.

“Dawn's residence at Vesta of nearly a year has made the asteroid's planet-like qualities obvious and shown us our connection to that bright orb in our night sky,” added the expert, who is the deputy principal investigator for the mission. Raymond is based at the NASA Jet Propulsion Laboratory, in Pasadena, California.

Dawn revealed that multiple layers of rocks surround a large iron core at Vesta, one of the clearest pieces of evidence that the object could have developed into a fully-fledged planet. The central iron ball may be around 68 miles (110 kilometers) wide.

The asteroid was also confirmed to be the source of a special type of iron- and magnesium-rich meteorite called pyroxene. Astronomers hypothesized that these objects came from Vesta some time ago, but could not determine whether that was actually the case until now.

Statistically speaking, Vesta is one of the most important sources of meteorites for our planet, accounting for about 6 percent of all rocks that make their way through the atmosphere.

“We know a lot about the moon and we're only coming up to speed now on Vesta. Comparing the two gives us two storylines for how these fraternal twins evolved in the early solar system,” expert Vishnu Reddy said.

The expert holds an appointment as a framing camera team member at the Max Planck Institute for Solar System Research, in Germany. He is also based at the University of North Dakota in Grand Forks.

Dawn is currently scheduled to exit Vesta's orbit on August 26, and head out towards the dwarf planet Ceres immediately. The trip will take about three years, and investigators hope to have the spacecraft achieve orbital insertion around the largest Inner Asteroid Belt object by early 2015.