Vesta May Be a Reservoir of Water-Ice

Average temperatures on its surface certainly allow for that

Planetary scientists say that the giant asteroid Vesta may contain large amounts of water-ice, which may be able to endure there for billions of years. The conclusion came from a new analysis of the protoplanet's surface, as well as its average temperatures.

The NASA Dawn spacecraft has been orbiting Vesta since July 2011, and has since moved through a series of different orbits in its quest for the perfect vantage point. Its analyses are proving to be invaluable for researchers, who did not suspect the presence of water-ice on the massive object.

Vesta is the largest asteroid in our solar system. Some suggest that it's also a protoplanet, the embryo of a would-be planet that never got to grow to its full potential. One of Dawn's mission objectives is to figure out whether that was the case, and also what caused the object to stop growing.

Understanding this could lead to a deeper understanding of how planets and asteroids formed in the earliest days of the solar system. Further down the line, the study could also be useful in figuring out how the inner rocky planets formed, as well as why the solar system is set up the way it is today.

Experts were fairly surprised to see that water-ice may endure on the asteroid in such large amounts. They say that the accepted view of the space rock is that of a rather dry place. Yet, data collected by Dawn indicate that nearly half of the object is cold and dark enough to support permanent water-ice.

What's more, the analysis revealed that the chemical could endure on Vesta's dark regions for billions of years. These data were extracted from the very first model depicting the asteroid's average illumination by the Sun, as well as its average, overall temperatures.

“Near the north and south poles, the conditions appear to be favorable for water ice to exist beneath the surface,” explains researcher Timothy Stubbs, who holds joint appointments at the NASA Goddard Space Flight Center (GSFC), in Greenbelt, and the University of Maryland, in Baltimore.

Together with UM Goddard Planetary Heliophysics Institute expert Yongli Wang, Stubbs published the model of Vesta in the January issue of the esteemed scientific journal Icarus. Data from the NASA/ESA Hubble Space Telescope were also included in the simulation.

Discovering water-ice on Vesta also has practical applications, such as for example in manned space exploration of the solar system. The asteroid is large enough to provide a solid base of operations for future missions to go beyond the orbit on Earth, mars and the Moon.

“Our perceptions of Vesta have been transformed in a few months as the Dawn spacecraft has entered orbit and spiraled closer to its surface,” GSFC scientists and Dawn investigator Lucy McFadden says.

“More importantly, our new views of Vesta tell us about the early processes of solar system formation. If we can detect evidence for water beneath the surface, the next question will be is it very old or very young, and that would be exciting to ponder,” she concludes.

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