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vestamap.txt
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1996-01-12
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FOR RELEASE: October 10, 1995
PHOTO RELEASE NO.: STScI-PRC95-40
HUBBLE MAPS THE ASTEROID VESTA
These two maps are derived from images of asteroid 4 Vesta taken
between November 28 and December 1, 1994 with the Wide Field Planetary
Camera-2 (in PC mode) aboard NASA's Hubble Space Telescope. Hubble
images show surface details as small as 35 miles across. The mid
latitude region of Vesta, between about 16 degrees south and 48 degrees
north, were favorably situated for viewing from Earth at the time the
images were taken. Global coverage was obtained by taking multiple
images as Vesta rotated on its axis with a 5.34 hour period. Vesta is
320 miles in diameter, and the map covers a surface area of 200,000
miles.
[Top] Surface Brightness Map of Vesta - This map shows that, unlike
most asteroids, Vesta's surface is significantly varied with a dark
hemisphere and a light hemisphere. The surface markings may represent
ancient igneous activity such as lava flows and, in addition, regions
where major impacts have stripped away the crust revealing mantle
material below the crust. The name "Olbers" has been proposed for a
conspicuous dark circular feature that is 120 miles across. The
feature is named after astronomer H.W. Olbers, who discovered Vesta in
1807. The image was taken in blue light.
[Bottom] Surface Composition Map of Vesta - This false-color composite
map of Vesta results show that all of Vesta's surface is igneous,
indicating that either the entire surface was once melted, or lava
flowing from its interior once completely covered its surface. The
map shows that Vesta has two distinct hemispheres containing two
different types of solidified lava called basalts.
Current interpretations suggest the red-colored hemisphere has been
heavily excavated by impacts which have exposed the subsurface
material. This area is interpreted to be composed of a type of basalt
(rich in the mineral pyroxene) which forms when lava cools and
solidifies below a planet's surface. The hemisphere colored
yellow-green may be the remains of Vesta's ancient crust formed near
the time of the beginning of the solar system. This region is
interpreted to be composed of a type of basalt which is comprised by a
mixture of the minerals pyroxene and feldspar. This type of basalt is
formed by lava which cools and solidifies on the surface of a planet.
The region identified as "Olbers," and another dark green region at
longitude +80 degrees, appear to have a more complex history. They
could be regions where very deep impacts have punched through the
basaltic crust to expose darker material from the upper mantle of
Vesta, and mix it with the crustal lavas.
This map was produced from separate images in blue (439 nm), orange
(673 nm), red (953 nm), and near-infrared (1024 nm) light. The map is
produced in false colors to highlight regions of geologically
interesting regions on Vesta's surface.
Credit: Ben Zellner (Georgia Southern University) and NASA
Principal Investigator is Dr. Ben Zellner of Members of the science
team include Dr. Rudolph Albrecht of the Space Telescope European
Coordinating Facility, Dr. Richard P. Binzel of MIT, Dr. Michael Gaffey
of Rensellaer Polytechnic Institute, Dr. Alex Storrs of Space Telescope
Science Institute, Dr. Peter Thomas of Cornell, and Dr. Ed Wells of
Computer Sciences Corporation.
Image files in GIF and JPEG format may be accessed on Internet via
anonymous ftp from ftp.stsci.edu in /pubinfo. The same images are
available via World Wide Web from URL
http://www.stsci.edu/pubinfo/Latest.html,
or via links in http://www.stsci.edu/pubinfo/Pictures.html.
GIF JPEG
PRC95-40 Vesta Map gif/VestaMap.gif jpeg/VestaMap.jpg