4 Vesta : Ask Biography

Animation of Vesta taken by the Dawn spacecraft from orbit. Vesta completes a full rotation every 5.342 hours.

Planet information

Name

4 Vesta

Discovered by

Heinrich Wilhelm Olbers

Discovery date

March 29, 1807

Designation

Pronunciation

-enˈvɛstə,

Named after

Vesta

Minor planet
category

Main belt (Vesta family)

Adjective

Vestian, Vestan

Orbit

Epoch

May 14, 2008 (JD 2454600.5)

Aphelion

2.572 AU (384.72 Gm)

Perihelion

2.151 AU (321.82 Gm)

Semi-major axis

2.361 AU (353.268 Gm)

Eccentricity

0.089 17

Orbital period

3.63 a (1325.15 d)

Avg orbital speed

19.34 km/s

Mean anomaly

90.53°

Inclination

7.135° to Ecliptic
5.56° to Invariable plane

Longitude of ascending node

103.91°

Argument of peri

149.83°

Physical characteristics

Dimensions

578×560×458 km
529 km (mean)

Mass

(2.59) kg

Density

3.42 g/cm³

Equatorial surface gravity

0.22 m/s²
0.022 g

Escape velocity

0.35 km/s

Rotation period

0.222 6 d (5.342 h)

Albedo

0.423 (geometric)

Temperature

min: 85 K (−188 °C)
max: 270 K (−3 °C)

Spectral type

V-type asteroid

Apparent magnitude

5.1 to 8.48

Absolute magnitude H

3.20

Angular diameter

0.64" to 0.20"

Home | Planet | 4 Vesta

Vesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about 530 km (329.3 mi). It was discovered by Heinrich Wilhelm Olbers on March 29, 1807 and is named after the Roman virgin goddess of home and hearth, Vesta.

Vesta is the second-most-massive asteroid after the dwarf planet Ceres, and comprises an estimated 9% of the mass of the asteroid belt.

The less-massive Pallas might have a larger volume, which would make Vesta third in overall size, but the precise dimensions of Pallas are not known. Vesta is thought to be a remnant protoplanet with a differentiated interior. It lost some 1% of its mass less than a billion years ago in a collision that left an enormous crater occupying much of its southern hemisphere. Debris from this event has fallen to Earth as Howardite � Eucrite � Diogenite (HED) meteorites, a rich source of information about the asteroid.

Vesta is the brightest asteroid. Its maximum distance from the Sun is slightly farther than the minimum distance of Ceres from the Sun, though its orbit lies entirely within the Cererian orbit.

NASA's Dawn spacecraft entered orbit around Vesta on July 16, 2011 for a planned one-year exploration, and what is known about Vesta will be refined and extended as data from Dawn is received, analyzed and published.