Space

April 25, 2012

NASA Dawn spacecraft reveals secrets of giant asteroid Vesta

Findings from NASA’s Dawn spacecraft reveal new details about the giant asteroid Vesta, including its varied surface composition, sharp temperature changes and clues to its internal structure.

The findings were presented today at the European Geosciences Union meeting in Vienna, Austria and will help scientists better understand the early solar system and processes that dominated its formation.

Spacecraft images, taken 420 miles and 130 miles above the surface of the asteroid, show a variety of surface mineral and rock patterns. Coded false-color images help scientists better understand Vesta’s composition and enable them to identify material that was once molten below the asteroid’s surface.

Researchers also see breccias, which are rocks fused during impacts from space debris. Many of the materials seen by Dawn are composed of iron- and magnesium-rich minerals, which often are found in Earth’s volcanic rocks. Images also reveal smooth pond-like deposits, which might have formed as fine dust created during impacts settled into low regions.

“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 Munster University in Germany. “The images suggest an amazing variety of processes that paint Vesta’s surface.”

At the Tarpeia crater near the south pole of the asteroid, Dawn revealed bands of minerals that appear as brilliant layers on the crater’s steep slopes. The exposed layering allows scientists to see farther back into the geological history of the giant asteroid.

The layers closer to the surface bear evidence of contamination from space rocks bombarding Vesta’s surface. Layers below preserve more of their original characteristics. Frequent landslides on the slopes of the craters also have revealed other hidden mineral patterns.

“These results from Dawn suggest Vesta’s ‘skin’ is constantly renewing,” said Maria Cristina De Sanctis, lead of the visible and infrared mapping spectrometer team based at Italy’s National Institute for Astrophysics in Rome.

Dawn has given scientists a near 3-D view into Vesta’s internal structure. By making ultrasensitive measurements of the asteroid’s gravitational tug on the spacecraft, Dawn can detect unusual densities within its outer layers. Data now show an anomalous area near Vesta’s south pole, suggesting denser material from a lower layer of Vesta has been exposed by the impact that created a feature called the Rheasilvia basin. The lighter, younger layers coating other parts of Vesta’s surface have been blasted away in the basin.

Dawn obtained the highest-resolution surface temperature maps of any asteroid visited by a spacecraft. Data reveal temperatures can vary from as warm as minus10 degrees Fahrenheit (minus 23 degrees Celsius) in the sunniest spots to as cold as minus 150 degrees Fahrenheit (minus 100 degrees Celsius) in the shadows. This is the lowest temperature measurable by Dawn. These findings show the surface responds quickly to illumination with no mitigating effect of an atmosphere.

“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 in Pasadena, Calif. “We are closing in on the giant asteroid’s secrets.”

Launched in 2007, Dawn began its exploration of the approximately 330-mile-wide asteroid in mid-2011. The spacecraft’s next assignment will be to study the dwarf planet Ceres in 2015. These two icons of the asteroid belt have been witness to much of our solar system’s history.

Dawn’s mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.

 

To view the new images and for more information about Dawn, visit http://www.nasa.gov/dawn.

 




All of this week's top headlines to your email every Friday.


 
 

 
NASA image

Ozone-depleting compound persists, NASA research shows

NASA image Satellites observed the largest ozone hole over Antarctica in 2006. Purple and blue represent areas of low ozone concentrations in the atmosphere; yellow and red are areas of higher concentrations. NASA research show...
 
 

NASA’s RXTE satellite decodes rhythm of an unusual black hole

https://www.youtube.com/embed/TSWZI2oUgnI?enablejsapi=1&rel=0 Astronomers have uncovered rhythmic pulsations from a rare type of black hole 12 million light-years away by sifting through archival data from NASA’s Rossi X-ray Timing Explorer satellite. The signals have helped astronomers identify an unusual midsize black hole called M82 X-1, which is the brightest X-ray source in a ga...
 
 

NASA announces awards to expand informal STEM education network

NASA has selected 12 informal educational institutions to receive approximately $6 million in agency funding to provide compelling science, technology, engineering and math opportunities in informal education settings, such as museums, science centers, planetariums and NASA visitor centers. The selected projects will complement and enhance STEM curricula taught in traditional kindergarten throu...
 

 

Orbital completes third cargo delivery mission to ISS

Orbital Sciences Corporation, one of the world’s leading space technology companies, announced Aug. 18 the successful completion of its third cargo delivery mission to the International Space Station in the past 10 months, including the initial demonstration flight completed in October 2013 and the first two operational missions under the company’s $1.9 billion Commercial Resupply...
 
 

NASA selects Texas State University to provide educator professional development

NASA’s Minority University Research and Education Project has awarded approximately $15 million in a new, five-year cooperative agreement to Texas State University at San Marcos to provide educator professional development using NASA-related science, technology, engineering and math content. The selection is in response to an Education Opportunities in NASA STEM ñ Educator Professional D...
 
 
Photograph courtesy of NASA/SAO/CXC/R. Margutti et al

NASA’s Chandra Observatory searches for trigger of nearby supernova

Photograph courtesy of NASA/SAO/CXC/R. Margutti et al NASA’s Chandra X-ray Observatory is helping determine what caused SN 2014J, one of the closest supernovas discovered in decades. By comparing X-ray data taken before and a...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>