4 Vesta

4 Vesta

Discoverer	H. Olbers - 1827.
Diameter (km)	530
Mass (kg)	*310^²⁰**
Rotation period (hrs)	5.342
Orbital period (yrs)	3.63
Semimajor axis (AU)	2.36085
Orbital eccentricity	0.08979
Orbital Inclination (deg)	7.13463
Albedo	0.42
Type	V

Vesta, is the eldest sister of Zeus but she chose to spend her time, not on Olympus, but on earth with the mortals. She has never wed but she protects orphans and missing children. She is the goddess of humble bomestic joy. She is also one of only three who are immune to the spells of Aphrodite, the other two are Athene and Artemisin Roman Mythology was the goddess of hearth fire. She was usually identified with Hestia, the Greek goddess of the hearth. Together with the Penates, the Roman household gods, Vesta was worshipped daily by every Roman Family. Her shrine was the hearth, which was the center of every Roman home. Vesta also had public shrines, and her worship was an important part of the Roman state religion. Newly appointed Roman political figures offered sacrifices to Vesta at her sanctuary in Lavinium before assuming their official duties. Her festival, known as Vestalia, was held in Rome every June. Vesta was never represented in human form but was believed to exist in the flames of her sacred fire.

Vesta is the most geologically diverse of the large asteroids and the only known one with distinctive light and dark areas much like the face of our Moon. Hubble images have revealed a diverse world with ancient lava flows and a gigantic impact basin that is so deep, it exposes the asteroid's subsurface, or mantle. Vesta's surface shows geology similar to that of terrestrial worlds. Ground-based spectroscopy of Vesta indicates regions that are basaltic, which means lava flows once occurred on its surface. This is surprising evidence that the asteroid once had a molten interior, like Earth does. This contradicts conventional ideas that asteroids are essentially cold, rocky fragments left behind from the early days of planetary formation.

This happened more than four billion years ago. The surface has remained unchanged since then, except for occasional meteoroid impacts.

One or more large impacts tore away some of the crust, exposing a deeper mantle of olivine which is believed to constitute most of the Earth's mantle. Astronomers believe that some of the pieces knocked off Vesta have fallen to Earth as meteorites, which show a similar spectral fingerprint to Vesta's surface composition.

Images of Vesta

	1994 Hubble Images of Vesta This sequence was taken with Hubble's Wide Field Planetary Camera 2 between November 28 and December 1, 1994, when Vesta was at a distance of 251 million kilometers (156 million miles) from Earth.
The set of 24 images shows the full 5.34-hour rotation of the 525-kilometer asteroid Vesta. Hubble resolved features as small as 56 kilometers across. (Credit: B. Zellner, Georgia Southern University/NASA)
	1996 Hubble Images of Vesta
The picture in the center is a elevation map of Vesta which clearly shows the giant 285-mile diameter impact basin and central peak. The map was constructed from 78 Wide Field Planetary Camera 2 pictures. The picture on the right shows a 3-D computer model of the asteroid Vesta synthesized from Hubble topographic data. The crater's 8-mile high central peak can clearly be seen near the pole. (Credit: B. Zellner, Georgia Southern University; Peter Thomas, Cornell University; NASA)
	1999 Keck II Images of Vesta
	Surface Map of Vesta These two maps are derived from images of asteroid 4 Vesta taken between November 28 and December 1, 1994, by the Hubble Space Telescope. The mid-latitude region of Vesta, between about 16° south and 48° north, were favorably situated for viewing from Earth at the time the images were taken. The map covers a surface area of 518,000 kilometers (200,000 miles).
The top, surface brightness 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 bottom map is a false-color composite showing 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. It also shows that Vesta has two distinct hemispheres containing two different types of solidified lava basalt. Current interpretations suggest the red-colored hemisphere has been heavily excavated by impacts that have exposed the subsurface material. The yellow-green colored hemisphere might be the remains of Vesta's ancient crust, formed near the time of the beginning of the solar system. (Credit: B. Zellner, Georgia Southern University/NASA)
	Vesta Meteorite This meteorite is assumed to be a piece of the Vesta's crust. The meteorite is unique because it is made almost entirely of the mineral pyroxene, common in lava flows. The meteorite's chemical identity points to the asteroid Vesta because it has the same unique spectral signature of the mineral pyroxene.
The meteorite's mineral grain structure also indicates it was once molten, and its oxygen isotopes are unlike oxygen isotopes found for all other rocks of the Earth and Moon.

Animations of Vesta
Vesta's Model in Rotation	Hubble 1994 Images of Vesta

Last updated: March 15, 2002.