| • Science | • People | • Locations | • Timeline |
| Discovery | |
|---|---|
| Discoverer | Heinrich Wilhelm Olbers |
| Discovery Date | March 28, 1802 |
| Alternate Designations | |
| Category | Main belt |
| Orbital Elements Epoch July 14, 2004 ( JD 2453200.5) | |
| Eccentricity (e) | 0.230 |
| Semi-Major Axis (a) | 414.717 G m (2.772 AU) |
| Perihelion (q) | 319.358 Gm (2.135 AU) |
| Aphelion (Q) | 510.077 Gm (3.410 AU) |
| Orbital Period (P) | 1685.927 d (4.62 a) |
| Mean Orbital Speed | 17.89 km/ s |
| Inclination (i) | 34.852 ° |
| Longitude of the Ascending Node (Ω) | 173.166° |
| Argument of Perihelion (ω) | 310.529° |
| Mean Anomaly (M) | 346.022° |
| Physical Characteristics | |
| Dimensions | 570×525×482 km |
| Mass | 2.06×1020 kgThe kilogram (symbol: kg is the SI base unit of mass. A gram is defined as one thousandth of a kilogram. Conversion of units describes equivalent units of mass in other systems. Multiples SI prefixes are used to name multiples and subdivisions of the kilo |
| Density | 4.2 g/ cCenti can also stand for Centro Internacional de Teoterapia Integral (International Center of Integral Teotheraphy). Centi (symbol c is a SI prefix in the SI system of units denoting a factor of 10-2, or 1/100. Adopted in 1795, the prefix comes from the L m³The cubic metre (symbol m is the SI derived unit of volume. It is the volume of a cube with edges one metre in length. Older, now unofficial, equivalents were the stere and the kilolitre. 1 cubic metre is equal to: 1,000 litres 1,000 cubic decimetres 1, |
| Surface Gravity | 0.16 m/s² |
| Escape Velocity | 0.35 km/s |
| Rotation Period | 0.32555 d |
| Spectral Class | U |
| Absolute Magnitude | 4.13 |
| Albedo | 0.159 |
| Mean Surface Temperature | ~226 K |
Pallas is the second largest Main belt asteroid. Its orbit is located in the central part of the belt but it is somewhat inclined and eccentric for a large asteroid. The composition of Pallas is unique but quite similar to the C-type asteroids.
Pallas has been observed occulting a star several times. Careful occultation timing measurements have helped give it an accurate diameter.
During the occultation of May 29, 1979 the discovery of a possible tiny satellite with a diameter of ~1 km was reported. However, it has not been confirmed. In 1980, speckle interferometry was reported as indicating a much larger satellite with a diameter of 175 km, but the existence of the satellite was later refuted. (1)
Pallas has not yet been visited by a spacecraft, but if the Dawn probe is successful in studying 1 Ceres and 4 Vesta, its mission may be extended to Pallas.
The chemical element palladium (atomic number 46) was named after Pallas.