Astronomy: NASA Dawn Spacecraft Reveals Secrets of Giant Asteroid Vesta

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., 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.

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Vibidia Crater in Color

These composite images from the framing camera aboard NASA’s Dawn spacecraft show three views of the comparatively fresh crater named Vibidia on the giant asteroid Vesta. A black-and-white image that highlights topography, a colorized image that highlights composition and a combination of the black-and-white and colorized images to show the relationship between topography and composition are included here.

The impact that created Vibidia occurred at the edge of a cratered highland in the equatorial region and extends to a basin known as Veneneia. It appears to be located in a gentle depression, presumably an older crater. Scientists think a relatively small object caused the crater, which features many boulders inside and rays of dark material. As on the moon, bright rays can be the result of compositional differences in material thrown out by the impact compared to the surrounding terrain. Or bright rays can indicate differences in maturity -- that is, the amount of time the surface has been exposed to subsequent bombardment by micrometeoroids and cosmic rays. Vibidia exhibits a particularly colorful blanket of ejected material, demonstrating that the surface and the layer just beneath are made up of many different kinds of materials. These patterns reflect a complex interplay of ancient volcanic and impact processes that shaped Vesta’s crust. The impact that created Vibidia also appears to have caused an area with a width five times the diameter of the crater to collapse.

The framing camera has seven color filters that allow it to image Vesta in a number of different wavelengths of light. Being able to image in many wavelengths enhances features and colors that would otherwise be indistinguishable to the human eye. In this colorized image, scientists assigned different color channels to specific ratios of wavelengths of radiation. In this scheme, green shows the relative strength of a particular mineralogical characteristic -- the absorption of iron. Brighter green signifies a higher relative strength of this band, which indicates chemistry involving pyroxene. On the other hand, reddish colors indicate either a different mineralogy or a stronger weathered surface.

These images are composite images made from those taken during Dawn’s high-altitude mapping orbit (420 miles or 680 kilometers above the surface) on Oct 27, 2011. They cover an area that is about 40 by 40 miles (60 by 60 kilometers). This area is near the edge of the Rheasilvia basin in Vesta’s southern hemisphere.

The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. UCLA is responsible for overall Dawn mission science. The Dawn framing cameras were developed and built under the leadership of the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, with significant contributions by DLR German Aerospace Center, Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The Framing Camera project is funded by the Max Planck Society, DLR, and NASA/JPL.

More information about Dawn is online at http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov/ .

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

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Tarpeia Crater, Close, Closer, Closest

These images of Tarpeia crater, near the south pole of the giant asteroid Vesta, were obtained by the visible and infrared mapping spectrometer on NASA’s Dawn spacecraft. Colorized versions of the images show younger material with abundant pyroxene (an iron- and magnesium-rich material) and older layers with less pyroxene.

The visible and infrared mapping spectrometer obtained the images during Dawn’s survey orbit (1,700 miles or 2,750 kilometers in altitude) on Aug. 21, 2011; high-altitude mapping orbit (420 miles or 680 kilometers above the surface) on Oct. 9, 2011; and low-altitude mapping orbit (130 miles or 210 kilometers in altitude) on Feb. 5, 2012.

In the colorized images, scientists assigned red to the 1.9-micron wavelength of reflected light, green to the 1.5-micron wavelength and blue to the 1.2-micron wavelength. In the resulting image, the brown and yellow materials have similar composition, but the brown material receives less illumination from sunlight and appears darker. The material on the edge of the crater rim that appears blue in these images suggests a different, fresher material. This material must have been exposed during a landslide or a similar recent event that occurred on the side of the crater. Researchers think the blue areas have been less altered over time, preserving more of the original material of Vesta.

The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. UCLA is responsible for overall Dawn mission science. The visible and infrared mapping spectrometer was provided by the Italian Space Agency and is managed by the Italy’s National Institute for Astrophysics, Rome, in collaboration with Selex Galileo, where it was built.

More information about Dawn is online at http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov/.

Image credit: NASA/JPL-Caltech/UCLA/INAF

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Tarpeia Temperature

This colorized image from NASA’s Dawn mission shows temperature variations at Tarpeia crater, near the south pole of the giant asteroid Vesta. It was obtained by the visible and infrared mapping spectrometer. The white areas are the warmest, measuring about minus 10 degrees Fahrenheit (minus 23 degrees Celsius). The dark areas are the coldest, with temperatures at or below minus 150 degrees Fahrenheit (minus 100 degrees Celsius), the bottom of the visible and infrared mapping spectrometer’s range.

The variations in the red shading indicate the intensity of the reflected light in the 5-micron wavelength, which is indicative of the surface temperature.

The visible and infrared mapping spectrometer obtained the images during Dawn’s low-altitude mapping orbit (130 miles or 210 kilometers in altitude) on Feb. 5, 2012.

The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. UCLA is responsible for overall Dawn mission science. The visible and infrared mapping spectrometer was provided by the Italian Space Agency and is managed by the Italy’s National Institute for Astrophysics, Rome, in collaboration with Selex Galileo, where it was built.

More information about Dawn is online at http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov/ .

Image credit: NASA/JPL-Caltech/UCLA/INAF

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Shape and Gravity of Vesta's South Pole

This set of images from NASA's Dawn mission shows topography of the southern hemisphere of the giant asteroid Vesta and a map of Vesta's gravity variations that have been adjusted to account for Vesta's shape. The shaded relief map on the left shows the outlines of the two ancient basins, Rheasilvia and Veneneia. On the right is a map of the residual gravity field created by removing the gravity due to the hills and valleys within the crustal layer, revealing the signature of variations in density.

Red shows the strongest gravitational pull in this scheme, measured in milligal units, and dark blue shows the weakest. Milligals are a unit of acceleration due to gravity. The large central peak of the Rheasilvia basin, which appears as the yellow area just above and to the left of center, has a small positive residual gravity anomaly. This indicates the crust there is denser, coming from deeper within the body, or perhaps is less fractured. The gravity lows near the basin rim on the right, shown in dark blue, likely indicate rock that is lighter as a result of being pulverized by the two impacts.

The topography model is derived from framing camera images from Dawn's high-altitude mapping orbit (420 miles or 680 kilometers above the surface) and the gravity data come from the low-altitude mapping orbit (130 miles or 210 kilometers above the surface).

Dawn's mission to Vesta and Ceres is managed by JPL for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena. 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.

More information about Dawn is online at http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov/ .

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn Reveals Secrets of Giant Asteroid Vesta:

PASADENA, Calif. – 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.

Images from Dawn's framing camera and visible and infrared mapping spectrometer, taken 420 miles (680 kilometers) and 130 miles (210 kilometers) 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 Münster 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 imagery 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 asteroid's surface bear evidence of contamination from space rocks bombarding Vesta. 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 ultra-sensitive 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 minus 10 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's visible and infrared mapping spectrometer. 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 (530-kilometers) 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. The California Institute of Technology in Pasadena manages JPL for NASA.

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

Guillermo Gonzalo Sánchez Achutegui

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