VESTA

MINOR PLANET 4 VESTA

THE NEXT OPPOSITION OF VESTA WILL BE ON 2012 DEC 9 AT MAGNITUDE 6.4 - DECLINATION +17 DEGREES

THE LAST OPPOSITION OF VESTA OCCURRED ON 2011 AUGUST 5 - MAGNITUDE +5.6

NOTE THAT VESTA IS MOVING TO THE RIGHT IN THE FRAMES ABOVE. IF YOU DO NOT SEE IT LABELLED

IN THE FRAME AT THE RIGHT, IT HAS ALSO MOVED TO THE RIGHT OF THE SMALL BOX IN THE LEFT FRAME.

FULL ROTATION MOVIE OF VESTA FROM DAWN:

Space Mountain Produces Terrestrial Meteorites

Dec. 30, 2011: When NASA's Dawn spacecraft entered orbit around giant asteroid Vesta in July, scientists fully expected the probe to reveal some surprising sights. But no one expected a 13-mile high mountain, two and a half times higher than Mount Everest, to be one of them.

The existence of this towering peak could solve a longstanding mystery: How did so many pieces of Vesta end up right here on our own planet?

A side view of Vesta's great south polar mountain. [more]

For many years, researchers have been collecting Vesta meteorites from "fall sites" around the world. The rocks' chemical fingerprints leave little doubt that they came from the giant asteroid. Earth has been peppered by so many fragments of Vesta, that people have actually witnessed fireballs caused by the meteoroids tearing through our atmosphere. Recent examples include falls near the African village of Bilanga Yanga in October 1999 and outside Millbillillie, Australia, in October 1960.

"Those meteorites just might be pieces of the basin excavated when Vesta's giant mountain formed," says Dawn PI Chris Russell of UCLA.

Russell believes the mountain was created by a 'big bad impact' with a smaller body; material displaced in the smashup rebounded and expanded upward to form a towering peak. The same tremendous collision that created the mountain might have hurled splinters of Vesta toward Earth.

"Some of the meteorites in our museums and labs," he says, "could be fragments of Vesta formed in the impact -- pieces of the same stuff the mountain itself is made of."

To confirm the theory, Dawn's science team will try to prove that Vesta's meteorites came from the mountain's vicinity. It's a "match game" involving both age and chemistry.

"Vesta formed at the dawn of the solar system," says Russell. "Billions of years of collisions with other space rocks have given it a densely cratered surface."

The surface around the mountain, however, is tellingly smooth. Russell believes the impact wiped out the entire history of cratering in the vicinity. By counting craters that have accumulated since then, researchers can estimate the age of the landscape.

Cross-section of the south polar mountain on Vesta with the cross sections of Olympus Mons on Mars, the largest mountain in the solar system, and the Big lsland of Hawaii as measured from the floor of the Pacific, the largest mountain on Earth. These latter two mountains are both shield volcanoes.Credit: Russell et. al. (2011), EPSC

"In this way we can figure out the approximate age of the mountain's surface. Using radioactive dating, we can also tell when the meteorites were 'liberated' from Vesta. A match between those dates would be compelling evidence of a meteorite-mountain connection."

For more proof, the scientists will compare the meteorites' chemical makeup to that of the mountain area.

"Vesta is intrinsically but subtly colorful. Dawn's sensors can detect slight color variations in Vesta's minerals, so we can map regions of chemicals and minerals that have emerged on the surface. Then we'll compare these colors to those of the meteorites."

Could an impact on Vesta really fill so many museum display cases on Earth? Stay tuned for answers..

Author: Dauna Coulter | Editor: Dr. Tony Phillips | Credit: Science@NASA

Closer and Closer to the Vesta Surface

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December 21, 2011 - PASADENA, Calif. -- NASA’s Dawn Spacecraft has spiraled closer and closer to the surface of the giant asteroid Vesta. These images were obtained by Dawn’s framing camera in the three phases of its campaign since arriving at Vesta in mid-2011.

The two images on the left represent an identical area, first observed during Dawn's survey orbit (far left image). That orbit aimed to obtain a global characterization of the asteroid. The picture in the center is from Dawn's high-altitude mapping orbit (HAMO) when the surface was systematically imaged during September and October 2011 from an altitude of about 430 miles (700 kilometers) with about 230 feet (70 meters-per-pixel) resolution for global high-resolution stereo image data that were used to develop a global shape model and topographic maps.

Since Dec. 12, 2011, the orbiter has been circling Vesta in a slightly elliptical orbit known as low-altitude mapping orbit (LAMO) at an average 130 miles (210 kilometers) above the asteroid's surface. The image on the right was obtained on Dec. 13 from an altitude of 124 miles (199 kilometers) to the surface and has a resolution of 75 feet (23 meters) per pixel. It covers an area about 12 miles by 12 miles (19 kilometers by 19 kilometers).

The low altitude image has a resolution more than three times better than the resolution from the HAMO phase. There is a lot more detail in the image, like small impact craters or slumping at the steep-flanked mountain in the image center that can be identified in the two images to the left. The center of the LAMO image is at about 45.5 degrees south latitude and 325.1 degrees east longitude.

The Dawn mission to the asteroids 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 have been 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.

For more information about the Dawn mission, visit: http://www.nasa.gov/dawn.

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

« See Vesta by Dawn Gallery

Is Vesta the "Smallest Terrestrial Planet?"

Dec 9, 2011: NASA's Dawn spacecraft spent the last four years voyaging to asteroid Vesta – and may have found a planet.

Vesta was discovered over two hundred years ago but, until Dawn, has been seen only as an indistinct blur and considered little more than a large, rocky body. Now the spacecraft's instruments are revealing the true complexity of this ancient world.

"We're seeing enormous mountains, valleys, hills, cliffs, troughs, ridges, craters of all sizes, and plains," says Chris Russell, Dawn principal investigator from UCLA. "Vesta is not a simple ball of rock. This is a world with a rich geochemical history. It has quite a story to tell!"

Like Earth and other terrestrial planets, Vesta has ancient basaltic lava flows on the surface and a large iron core. It also has tectonic features, troughs, ridges, cliffs, hills and a giant mountain. False colors in this montage represent different rock and mineral types. [more] [video]

In fact, the asteroid is so complex that Russell and members of his team are calling it the "smallest terrestrial planet."

Vesta has an iron core, notes Russell, and its surface features indicate that the asteroid is "differentiated" like the terrestrial planets Earth, Mercury, Mars, and Venus.

Differentiation is what happens when the interior of an active planet gets hot enough to melt, separating its materials into layers. The light material floats to the top while the heavy elements, such as iron and nickel, sink to the center of the planet.

Researchers believe this process also happened to Vesta.

The story begins about 4.57 billion years ago, when the planets of the Solar System started forming from the primordial solar nebula. As Jupiter gathered itself together, its powerful gravity stirred up the material in the asteroid belt so objects there could no longer coalesce. Vesta was in the process of growing into a full-fledged planet when Jupiter interrupted the process.

Like Earth and other terrestrial planets, Vesta is differentiated into layers.

Although Vesta’s growth was stunted, it is still differentiated like a true planet.

"We believe that the Solar System received an extra slug of radioactive aluminum and iron from a nearby supernova explosion at the time Vesta was forming," explains Russell.

"These materials decay and give off heat. As the asteroid was gathering material up into a big ball of rock, it was also trapping the heat inside itself."

As Vesta’s core melted, lighter materials rose to the surface, forming volcanoes and mountains and lava flows.

"We think Vesta had volcanoes and flowing lava at one time, although we've not yet found any ancient volcanoes there," says Russell. "We're still looking. Vesta's plains seem similar

to Hawaii's surface, which is basaltic lava solidified after flowing onto the surface.

Vesta has so much in common with the terrestrial planets, should it be formally reclassified from "asteroid" to "dwarf planet"?

"That's up to the International Astronomical Union, but at least on the inside, Vesta is doing all the things a planet does."

If anyone asks Russell, he knows how he would vote.

Author: Dauna Coulter | Editor: Dr. Tony Phillips | Credit: Science@NASA

NEW CLOSE UP PHOTO OF VESTA'S SOUTH POLAR REGION FROM DAWN

This composite image shows the comparative sizes of eight asteroids. Until now, Lutetia, with a diameter of 81 miles (130 kilometers), was the largest asteroid visited by a spacecraft, which occurred during a flyby. Vesta, which is also considered a protoplanet because it's a large body that almost became a planet, dwarfs all other small bodies in this image, with diameter of approximately 330 miles (530 km).

NASA Spacecraft Entered Large Asteroid's Orbit on 2011 July 15

July 14, 2011: On July 15, NASA's ion-propelled Dawn probe became the first spacecraft to enter orbit around a main-belt asteroid. Dawn will orbit Vesta for one Earth-year, studying the giant space rock at close range to help scientists understand the earliest chapter of our solar system's history.

As Dawn approaches Vesta, surface details are coming into focus, as seen in a recent image taken from a distance of about 26,000 miles (41,000 kilometers):

NASA's Dawn spacecraft obtained this image of giant asteroid Vesta on July 9, 2011, from a distance of about 26,000 miles (41,000 kilometers).

Each pixel in the image corresponds to roughly 2.4 miles (3.8 kilometers). [more]

Engineers expect the spacecraft to be captured into orbit at approximately 10 PM PDT Friday, July 15 = 1 AM EDT on Sat, July 16.

They expect to hear from the spacecraft and confirm that it performed as planned during a scheduled communications pass that starts at approximately 11:30 PM PDT on Saturday, July 16 = 2:30 AM EDT on Sunday, July 17. When Vesta captures Dawn into its orbit, engineers estimate there will be approximately 9,900 miles (16,000 kilometers) between them. At that point, the spacecraft and asteroid will be approximately 117 million miles

(188 million kilometers) from Earth.

"It has taken nearly four years to get to this point," said Robert Mase, Dawn project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Our latest tests and check-outs show that Dawn is right on target and performing normally."

Engineers have been subtly shaping Dawn's trajectory for years to match Vesta's orbit around the sun. Unlike other missions, where dramatic propulsive burns put spacecraft into orbit around a planet, Dawn will ease up next to Vesta. Then the asteroid's gravity will capture the spacecraft into orbit. However, until Dawn nears Vesta and makes accurate measurements, the asteroid's mass and gravity will only be estimates. The Dawn team will refine the exact moment of orbit capture over the next few days.

Launched in September 2007, Dawn will depart for its second destination, the dwarf planet Ceres, in July 2012.

The spacecraft will be the first to orbit two bodies in our solar system.

Editor: Dr. Tony Phillips | Credit: Science@NASA

2011 CHARTS AND DATA BELOW ARE FROM NAKED-EYE PLANETS

Note that because of Vesta's relatively high orbital inclination (the angle of the orbital plane relative to the ecliptic) of 7°.1, it frequently passes through the non-zodiac constellations Cetus and Orion, often making long, steeply-inclined curves as it moves from prograde motion to retrograde motion and vice versa.

Much like Mars, Vesta does not reach opposition every year because its orbital motion is too fast to bring it back in line with both the Earth and the Sun within the course of one Earth year. In planetary studies, the period between two successive oppositions is known as the synodic period; the period reduces the further from the Sun the planet is situated. Vesta has a mean synodic period of 1.38 yrs (463.88 days) hence oppositions occur, on average, about every 1 year 4½ months.⁷

To the naked-eye under ideally dark conditions, Vesta appears as a faint, star-like point of light near the limit of detection. Although unspectacular, its motion can be detected against the background stars from one night to the next - a process which can easily be detected with a tripod-mounted camera. This is the standard method by which asteroids are identified, and indeed this is how they have historically been discovered. Similarly, any camera or telescope set to track the motion of the stars at high magnification across the sky over a long period of time will often detect asteroids since the latter will appear trailed, moving at a rate of motion differing from that of the background stars. Asteroids were once nicknamed 'the vermin of the skies' because their trails often spoiled long-exposure photographs of other objects being photographed by observatories across the world. Today, with the very large numbers of asteroids known to exist and the potential threat posed by near-Earth asteroids (NEAs) most astronomers treat them with considerably more respect.

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NASA Dawn Spacecraft Returns Close-Up Image of Asteroid Vesta (BELOW)

2011 July 18

This is the first image obtained by NASA's Dawn spacecraft after successfully entering orbit around Vesta.

Picture was taken on July 17 at a distance of 9500 miles. Each pixel represents 0.88 miles.

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

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› Enhanced view

This anaglyph image of the asteroid Vesta was taken on July 9, 2011 by the framing camera instrument aboard NASA's Dawn spacecraft. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

› Full image and caption

This composite image shows the comparative sizes of eight asteroids. Image credit: NASA/JPL-Caltech/JAXA/ESA

› Full image and caption

PASADENA, Calif. -- NASA's Dawn spacecraft has returned the first close-up image after beginning its orbit around the giant asteroid Vesta. On Friday, July 15, Dawn became the first probe to enter orbit around an object in the main asteroid belt between Mars and Jupiter.

The image taken for navigation purposes shows Vesta in greater detail than ever before. When Vesta captured Dawn into its orbit, there were approximately 9,900 miles (16,000 kilometers) between the spacecraft and asteroid. Engineers estimate the orbit capture took place at 10 p.m. PDT Friday, July 15 (1 a.m. EDT Saturday, July 16).

Vesta is 330 miles (530 kilometers) in diameter and the second most massive object in the asteroid belt. Ground- and space-based telescopes have obtained images of Vesta for about two centuries, but they have not been able to see much detail on its surface. "We are beginning the study of arguably the oldest extant primordial surface in the solar system," said Dawn principal investigator Christopher Russell from the University of California, Los Angeles. "This region of space has been ignored for far too long. So far, the images received to date reveal a complex surface that seems to have preserved some of the earliest events in Vesta's history, as well as logging the onslaught that Vesta has suffered in the intervening eons."

Vesta is thought to be the source of a large number of meteorites that fall to Earth. Vesta and its new NASA neighbor, Dawn, are currently approximately 117 million miles (188 million kilometers) away from Earth. The Dawn team will begin gathering science data in August. Observations will provide unprecedented data to help scientists understand the earliest chapter of our solar system. The data also will help pave the way for future human space missions.

After traveling nearly four years and 1.7 billion miles (2.8 billion kilometers), Dawn also accomplished the largest propulsive acceleration of any spacecraft, with a change in velocity of more than 4.2 miles per second (6.7 kilometers per second), due to its ion engines. The engines expel ions to create thrust and provide higher spacecraft speeds than any other technology currently available. "Dawn slipped gently into orbit with the same grace it has displayed during its years of ion thrusting through interplanetary space," said Marc Rayman, Dawn chief engineer and mission manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It is fantastically exciting that we will begin providing humankind its first detailed views of one of the last unexplored worlds in the inner solar system."

Although orbit capture is complete, the approach phase will continue for about three weeks. During approach, the Dawn team will continue a search for possible moons around the asteroid; obtain more images for navigation; observe Vesta's physical properties; and obtain calibration data.

In addition, navigators will measure the strength of Vesta's gravitational tug on the spacecraft to compute the asteroid's mass with much greater accuracy than has been previously available. That will allow them to refine the time of orbit insertion.

Dawn will spend one year orbiting Vesta, then travel to a second destination, the dwarf planet Ceres, arriving in February 2015. The mission to Vesta and Ceres is managed by JPL for the agency's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, which is managed by NASA's Marshall Space Flight Center in Huntsville, Ala.

UCLA is responsible for Dawn mission science. Orbital Sciences Corp. of 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 part of the mission's team.

To view the image and obtain more information about the Dawn mission, visit: http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov .

To follow the mission on Twitter, visit: http://www.twitter.com/NASA_Dawn .

Priscilla Vega 818-354-1357

Jet Propulsion Laboratory, Pasadena, Calif.

priscilla.r.vega@jpl.nasa.gov

Dwayne Brown 202-358-1726

NASA Headquarters, Washington

dwayne.c.brown@nasa.gov

2011-213

3-D IMAGE OF VESTA

February 16th, 2010 from UniverseToday.com

Asteroid Might be Visible to Naked Eye on 2010 Feb. 17

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When is an Asteroid Not an Asteroid?

2011 March 29

This image shows a model of the protoplanet Vesta, using scientists' best guess to date of what the surface of the protoplanet might look like. Image credit: NASA/JPL-Caltech/UCLA/PSI

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On March 29, 1807, German astronomer Heinrich Wilhelm Olbers spotted Vesta as a pinprick of light in the sky. Two hundred and four years later, as NASA's Dawn spacecraft prepares to begin orbiting this intriguing world, scientists now know how special this world is, even if there has been some debate on how to classify it.

Vesta is most commonly called an asteroid because it lies in the orbiting rubble patch known as the main asteroid belt between Mars and Jupiter. But the vast majority of objects in the main belt are lightweights, 100-kilometers-wide (about 60-miles wide) or smaller, compared with Vesta, which is about 530 kilometers (330 miles) across on average. In fact, numerous bits of Vesta ejected by collisions with other objects have been identified in the main belt.

"I don't think Vesta should be called an asteroid," said Tom McCord, a Dawn co-investigator based at the Bear Fight Institute, Winthrop, Wash. "Not only is Vesta so much larger, but it's an evolved object, unlike most things we call asteroids."

The layered structure of Vesta (core, mantle and crust) is the key trait that makes Vesta more like planets such as Earth, Venus and Mars than the other asteroids, McCord said. Like the planets, Vesta had sufficient radioactive material inside when it coalesced, releasing heat that melted rock and enabled lighter layers to float to the outside. Scientists call this process differentiation.

McCord and colleagues were the first to discover that Vesta was likely differentiated when special detectors on their telescopes in 1972 picked up the signature of basalt. That meant that the body had to have melted at one time.

Officially, Vesta is a "minor planet" -- a body that orbits the sun but is not a proper planet or comet. But there are more than 540,000 minor planets in our solar system, so the label doesn't give Vesta much distinction. Dwarf planets – which include Dawn's second destination, Ceres -- are another category, but Vesta doesn't qualify as one of those. For one thing, Vesta isn't quite large enough.

Dawn scientists prefer to think of Vesta as a protoplanet because it is a dense, layered body that orbits the sun and began in the same fashion as Mercury, Venus, Earth and Mars, but somehow never fully developed. In the swinging early history of the solar system, objects became planets by merging with other Vesta-sized objects. But Vesta never found a partner during the big dance, and the critical time passed. It may have had to do with the nearby presence of Jupiter, the neighborhood's gravitational superpower, disturbing the orbits of objects and hogging the dance partners.

Other space rocks have collided with Vesta and knocked off bits of it. Those became debris in the asteroid belt known as Vestoids, and even hundreds of meteorites that have ended up on Earth. But Vesta never collided with something of sufficient size to disrupt it, and it remained intact. As a result, Vesta is a time capsule from that earlier era.

"This gritty little protoplanet has survived bombardment in the asteroid belt for over 4.5 billion years, making its surface possibly the oldest planetary surface in the solar system," said Christopher Russell, Dawn's principal investigator, based at UCLA. "Studying Vesta will enable us to write a much better history of the solar system's turbulent youth."

Dawn's scientists and engineers have designed a master plan to investigate these special features of Vesta. When Dawn arrives at Vesta in July, the south pole will be in full sunlight, giving scientists a clear view of a huge crater at the south pole. That crater may reveal the layer cake of materials inside Vesta that will tell us how the body evolved after formation. The orbit design allows Dawn to map new terrain as the seasons progress over its 12-month visit. The spacecraft will make many measurements, including high-resolution data on surface composition, topography and texture. The spacecraft will also measure the tug of Vesta's gravity to learn more about its internal structure.

"Dawn's ion thrusters are gently carrying us toward Vesta, and the spacecraft is getting ready for its big year of exploration," said Marc Rayman, Dawn's chief engineer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We have designed our mission to get the most out of this opportunity to reveal the exciting secrets of this uncharted, exotic world."

The Dawn mission to Vesta and Ceres is managed by the Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. The Dawn mission is part of the Discovery Program managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corporation of Dulles, Va., designed and built the Dawn spacecraft. The German Aerospace Center, the Max Planck Society, the Italian Space Agency and the Italian National Astrophysical Institute are part of the mission team.

For more information about Dawn, visit http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov

Jia-Rui C. Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jia-rui.c.cook@jpl.nasa.gov

2011-100