| Risultati della ricerca nelle immagini - "Vesta" |
015-Ceres_and_Vesta.jpg4-Vesta and 1-Ceres from HST (natural colors)60 visiteThese Hubble Space Telescope images of Vesta and 1-Ceres show two of the most massive asteroids in the Asteroid Belt, a Region between Mars and Jupiter.
The images are helping astronomers plan for the Dawn spacecraft’s tour of these hefty asteroids. On July 7, 2007, NASA is scheduled to launch the spacecraft on a 4-year journey to the Asteroid Belt. Once there, Dawn will do some asteroid-hopping, going into orbit around Vesta in 2011 and Ceres in 2015. Dawn will be the first spacecraft to orbit two targets. At least 100.000 asteroids inhabit the Asteroid Belt, a reservoir of leftover material from the formation of our Solar-System planets some 4,6 Billion Years (BY) ago.MareKromium
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018-Vesta-6-PIA13428.jpgSome of the "Faces" of 4-Vesta, from Hubble Space Telescope97 visiteNASA's Hubble Space Telescope snapped these images of the Asteroid 4-Vesta in preparation for the Dawn Spacecraft's visit in 2011. Each of the 4 Hubble images captures views of Vesta during its 5,34-hour rotation period. Hubble's sharp "eye" can see features as small as about 40 Km (24,84 miles) across in these images. Vesta was 211 MKM (approx. 131 MMs) from Earth when Hubble made the observations.
The images show the difference in brightness and color on the Asteroid's Surface. These characteristics hint at the large-scale features that the Dawn Spacecraft will see when it visits the potato-shaped asteroid.
Astronomers used the images, taken with Hubble's Wide Field Camera 3, to better determine 4-Vesta's Spin Axis. Based on the HST observations, astronomers calculated a slightly different, and more precise, Rotation Axis for Vesta. The new calculation will change the pattern of sunlight expected to illuminate the Asteroid when Dawn arrives.
Determining a more accurate Spin Axis for 4-Vesta will also help scientists refine the Dawn Spacecraft's orbit around the Asteroid. Dawn will orbit the rocky object for a year, beginning in July 2011. The Spacecraft will then travel to the "Dwarf Planet" 1-Ceres, arriving in 2015.
Hubble has kept its "eye" on 4-Vesta for more than 15 years, beginning in 1994. Hubble images of 4-Vesta in 1997 helped astronomers discover the Asteroid's very large Impact crater. Astronomers combined views of 4-Vesta in Near-UltraViolet and blue light to construct these images and the images were taken on Feb. 25, 2010.MareKromium
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019-Vesta-5-PIA13427.jpg4-Vesta from Hubble Space Telescope105 visiteThe Asteroid 4-Vesta is somewhat like our Moon, with ancient Lava Beds (the dark patches) and powdery Debris (or Regolith), such as the pulverized remains of impacts (the orange-colored areas). A flattened area on one end of 4-Vesta is a giant Impact Crater formed by a collision that perhaps occurred billions of years ago.
The crater is approx. 460 Km (285,66 miles) across, which makes it close to 4-Vesta's roughly 530-Km (329,13-mile) diameter. The asteroid is about the size of Arizona.
4-Vesta is one of the largest of a reservoir of about 100.000 Asteroids, the leftover material from the formation of our Solar System.
Astronomers combined images of Vesta in Near-UltraViolet and blue light to make this picture movie. The Hubble observations were made on Feb. 25 and Feb. 28, 2010.MareKromium
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021-Vesta-2.jpg4-Vesta, from HST57 visiteHubble observation of Vesta: picture taken with the Wide Field Planetary Camera 2 on May 14 and 16, 2007.
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021-Vesta-3.jpgMoments of 4-Vesta56 visiteTo prepare for the Dawn spacecraft's visit to Vesta, astronomers used Hubble's Wide Field Planetary Camera 2 to snap new images of the asteroid. These images were taken on May 14 and 16, 2007. Each frame shows time in hours and minutes based on Vesta's 5,34-hour rotation period. Using Hubble, astronomers mapped Vesta's Southern Hemisphere, a Region dominated by a giant impact crater formed by a collision billions of years ago. The crater is 285 miles (456 Km) across, which is nearly equal to Vesta's 330-mile (530-Km) diameter.
Hubble's sharp "eye" can see features as small as about 37 miles (60 Km) across. The images show the difference in brightness and color on the asteroid's surface. These characteristics hint at the large-scale features that the Dawn spacecraft will see when it arrives at Vesta in 2011.
Hubble's view reveals extensive global features stretching longitudinally from the Northern Hemisphere to the Southern Hemisphere.
The images also show widespread differences in brightness in the east and west, which probably reflects compositional changes. Both of these characteristics could reveal volcanic activity throughout Vesta. The size of these different regions varies. Some are hundreds of miles across.
The brightness differences could be similar to the effect seen on the Moon, where smooth, dark regions are more iron-rich than the brighter highlands that contain minerals richer in calcium and aluminum. When Vesta was forming 4.5 billion years ago, it was heated to the melting temperatures of rock. This heating allowed heavier material to sink to Vesta's center and lighter minerals to rise to the surface.
Astronomers combined images of Vesta in two colors to study the variations in iron-bearing minerals. From these minerals, they hope to learn more about Vesta's surface structure and composition. Astronomers expect that Dawn will provide rich details about the asteroid's surface and interior structure.
MareKromium
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039-Vesta-PIA14121.jpgApproaching 4-Vesta81 visitenessun commentoMareKromium
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040-Vesta-PIA14122.jpgApproaching 4-Vesta82 visitenessun commentoMareKromium
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049-Vesta-PIA14124.jpg4-Vesta in Spectrometer View (Visible Light and IR)77 visiteCaption NASA:"On June 8, 2011, the Visible and InfraRed Mapping Spectrometer aboard NASA's Dawn Spacecraft captured the instrument's first images of 4-Vesta that are larger than a few pixels, from a distance of about 218.000 miles (approx. 351.000 Km). The images were taken for calibration purposes.
Images obtained in the Visible part of the light Spectrum, at about 0,55 microns in wavelength, appear on the left. Images obtained in the InfraRed Spectrum, at around 3 microns in wavelength, appear on the right. The spatial resolution of these images is about 60 miles (approx. 90 Km) per pixel.
The Visible and InfraRed mapping spectrometer will be able to provide images of 4-Vesta in 432 wavelengths, which will help scientists determine the basic composition of the Asteroid".MareKromium
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050-Vesta-HR_Video.gif4-Vesta: Full Rotation (a GIF-Movie by NASA / JPL / UCLA / MPS / DLR / PSI)106 visiteAs Dawn continued its approach to 4-Vesta on June 20, 2011, it occasionally quit thrusting and turned to the spinning Asteroid to perform a "rotation characterization," seeing all longitudes as 4-Vesta rotated beneath the Spacecraft.MareKromium
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051-569825main_dawn-image-070111-43_946-710.jpgApproaching 4-Vesta80 visitenessun commentoMareKromium
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052-569814main_dawn-image-062411-43_946-710.jpgApproaching 4-Vesta72 visitenessun commentoMareKromium
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053-Vesta-PIA14312.jpgFeatures of 4- Vesta (Saturated Absolute Natural Colors; credits for the additional process. and color: Dr Paolo C. Fienga - Lunexit Team)214 visiteCaption NASA:"NASA's Dawn Spacecraft obtained this image of the giant Asteroid 4-Vesta with its framing camera on July, 9, 2011. It was taken from a distance of about 26.000 miles (approx. 41.000 Km). 4-Vesta is also considered a "protoplanet" because it is a large body that almost became a planet. Each pixel in the image corresponds to roughly 2,4 miles (about 3,8 Km).
The Dawn mission to 4-Vesta and 1-Ceres is managed by the Jet Propulsion Laboratory, for NASA's Science Mission Directorate, Washington, D.C. It is a project of the Discovery Program managed by NASA's Marshall Space Flight Center, Huntsville, Ala. UCLA, is responsible for overall Dawn mission science. Orbital Sciences Corporation of Dulles, Va., designed and built the Dawn Spacecraft!".
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