16 Psyche
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A three-dimensional model of 16 Psyche based on its light curve.
|
|
| Discovery | |
|---|---|
| Discovered by | Annibale de Gasparis |
| Discovery date | 17 March 1852 |
| Designations | |
| Pronunciation | /ˈsaɪkiː/ SY-kee |
|
Named after
|
Psychē |
| none | |
| Main belt | |
| Orbital characteristics | |
| Epoch JD 2453300.5 (22 October 2004) | |
| Aphelion | 3.328 AU (497.884 Gm) |
| Perihelion | 2.513 AU (375.958 Gm) |
| 2.921 AU (436.921 Gm) | |
| Eccentricity | 0.140 |
| 4.99 yr (1823.115 d) | |
|
Average orbital speed
|
17.34 km/s |
| 323.379° | |
| Inclination | 3.095° |
| 150.352° | |
| 228.047° | |
| Physical characteristics | |
| Dimensions | 186 km (Geometric mean) 253.2 ± 4 km (IRAS) |
| Mass | 2.27×1019 kg |
|
Mean density
|
3.3 ± 0.7 g/cm³ |
| ~0.11 m/s² | |
| ~159 m/s | |
| 0.1748 d (4.196 h) | |
| Albedo | 0.120 (geometric) 0.29±0.11 (radar) |
| Temperature | ~160 K max: ~280 K (+7 °C) |
|
Spectral type
|
M |
| 9.22 to 12.19 | |
| 5.90 | |
16 Psyche is one of the ten most-massive asteroids in the asteroid belt. It is over 200 kilometers in diameter and contains a little less than 1% of the mass of the entire asteroid belt. It is thought to be the exposed iron core of a protoplanet. It is the most massive metallic M-type asteroid. Psyche was discovered by the Italian astronomer Annibale de Gasparis on 17 March 1852 from Naples and named after the Greek mythological figure Psyche.
The first fifteen asteroids to be discovered were given symbols by astronomers as a type of shorthand notation. Psyche was given an iconic symbol, as were several other asteroids discovered over the next few years. This symbol 
, a semicircle topped by a star, represents a butterfly's wing, symbol of the soul (psyche is the Greek word for 'soul'), and a star. In 1851, German astronomer J. F. Encke suggested using a circled number, and 16 Psyche was the first new asteroid to be discovered that was designated using this scheme when American astronomer J. Ferguson published his observations in 1852.
Radar observations indicate that Psyche has a fairly pure iron–nickel composition, consistent with it having the highest radar albedo of any asteroid in the asteroid belt (0.29±0.11). Psyche seems to have a surface that is 90% metallic (iron), with small amounts of pyroxene.
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Wikipedia