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4 Vesta
Asteroid (Dwarf Planet)
Actual |
Compared to Earth |
|
| Age | ~ 4.5 billion years | about the same age as the Sun |
| Actual Brightness | -- | -- |
| Location | Solar system, asteroid belt | -- |
| Avg. Distance from the Sun |
220 million miles | 2.4 au |
| Diameter | 330 miles (not spherical) | 0.04 |
| Mass | 3 x 1020 kg | -- |
| Density (gram/cubic cm) | -- | -- |
| Orbital Period around the Sun |
3.6 Earth years | 3.6 |
| Rotation Period | 5.3 hours | 3.6 |
| Surface Area | ~500,000 sq miles about the size of Pakistan |
-- |
| Surface Gravity | -- | -- |
| Surface Temperature (average) | -4 to -310 °F | -- |
| Number of moons | 0 | -- |
What To Look For Through The Telescope
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Recommended eyepiece: 26mm or 40 mm.
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Vesta resembles a star through the telescope. It is about the same brightness as Saturn’s moon Titan and a bit dimmer than Jupiter’s four Galilean moons. Vesta has an orange tint.
4 Vesta Information
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Vesta is the fourth asteroid ever discovered, thus the name “4 Vesta.” Vesta is named after the Roman goddess of hearth, home and family.
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Discovered by H.W. Olbers in March 29, 1807. After Ceres was discovered in 1801 and Pallas in 1802, Olbers theorized that there must be more, so he went asteroid hunting.
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It is the third largest asteroid in the asteroid belt, and it is the only asteroid that can be seen with the unaided eye (under very favorable viewing locations).
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Vesta is a very interesting asteroid.
a. Vesta is the most geologically diverse of the large asteroids, and the only one known with distinct light and dark areas.
b. Lava flows are found on the asteroid.
c. One impact crater is so deep it exposes the asteroid’s subsurface, or mantle.
d. It comprises almost 10% of all the mass in the asteroid belt.
e. Its most prominent feature is the Rheasilvia Crater, which stretches 313 miles across its face, covering 90% of the length of the asteroid. Its about 12 miles deep. This is one of the largest craters in the solar system.
f. The crater happened less than 1 billion years ago and shook off about 1% of the total mass of the asteroid.
g. This collision created the howardite-eucrite-diogenite (HED) meteorites, which comprise 5% of all the meteorites that fall to earth…so we already know quite a bit about the geology of Vesta.
h. It also contains deep grooves & troughs that would dwarf the Grand Canyon.
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On July 16, 2011, the Dawn spacecraft entered orbit around Vesta and 1 year of exploration. Dawn left Vesta on September 5, 2012 to head for Ceres.
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The light and dark areas on the asteroid correspond to different layers of the asteroid. This means the asteroid “differentiated” into layers long ago, like the terrestrial planets Mercury, Venus, Earth, and Mars.
a. First, start with an object in space, for example, the Earth.
b. Several different types of material with different densities are found in this object.
c. If the object is very, very hot, these materials melt.
d. Molten, more dense material sinks towards the center of the object while the molten, less dense material stays near the surface.
e. Differentiation can only occur if the object is very hot, otherwise, the dense materials would not melt and could not sink.
f. Long ago, Earth was very, very hot. Molten iron sunk to the core of Earth, while less dense materials stayed near the surface.
g. Since Vesta is differentiated, it means Vesta was once very hot.
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Two fence workers in Millbillillie, Western Australia, saw a fireball headed towards the ground in October, 1960. Ten years later, pieces of the fallen meteorite were found.
a. Signatures in the spectra (of light reflected off the surface) of the meteorite matches signatures in the spectra (of sunlight reflected off the surface) of Vesta: the meteorite is from Vesta.
b. Other small asteroids have recently been discovered near Vesta that have the same spectral signature as Vesta and the meteorite. These asteroids are considered chips blasted off of Vesta’s surface.
c. Other meteorites on Earth are probably from Vesta: they just haven’t been found or identified yet.
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References
| Item | Updated | Notes |
| Updated “View through telescope” info | 2003-03-21 | |
| Distance from Sun | 2017-04-305 | http://amazingspace.org/resource_page/79/solar_system/type#resource_tab |
| Revolution Period | 2017-04-30 | http://amazingspace.org/resource_page/79/solar_system/type#resource_tab |
| Rotation Period | 2003-02-05 | http://nssdc.gsfc.nasa.gov/planetary/factsheet/asteroidfact.html |
| Diameter | 2017-04-30 | http://amazingspace.org/resource_page/79/solar_system/type#resource_tab http://www.solarviews.com/eng/vesta.htm |
| Mass | 2017-04-30 | http://amazingspace.org/resource_page/79/solar_system/type#resource_tab |
| Surface Gravity | -- | |
| Temperature | -- | |
| Density | -- | |
| Other Information | 2003-02-05 | University of Cambridge’s Institute for Astronomy http://www.ast.cam.ac.uk/HST/press/vestamap.html Sites given above for other details http://www.hohmanntransfer.com/cat/a4.htm |