16 Psyche
| Orbital characteristics 1 (ftp://ftp.lowell.edu/pub/elgb/astorb.html) | |
|---|---|
| Orbit type | Main belt |
| Semimajor axis | 2.921 AU |
| Perihelion distance | 2.513 AU |
| Aphelion distance | 3.328 AU |
| Orbital period | 4.99 years |
| Inclination | 3.10° |
| Eccentricity | 0.140 |
| Physical characteristics | |
| Diameter | 250 km |
| Mass | 1.7 × 1019 kg |
| Density | 1.8 g/cm³ |
| Rotation period | 4.196 hours |
| Spectral class 1 (ftp://ftp.lowell.edu/pub/elgb/astorb.html) | M |
| Abs. magnitude 1 (ftp://ftp.lowell.edu/pub/elgb/astorb.html) | 5.90 |
| Albedo 4 (http://dorothy.as.arizona.edu/DSN/IRAS/index_iras.html) | 0.120 |
| History 2 (http://cfa-www.harvard.edu/iau/lists/NumberedMPs.html) | |
| Discoverer | A. de Gasparis, 1852 |
16 Psyche is the 13th-largest Main belt asteroid, measuring 250 kilometers in diameter.
It was discovered by Annibale de Gasparis on March 17, 1852 from Naples and named after the Greek nymph Psyche.
Spectral and other analyses indicate a fairly pure iron-nickel composition. Psyche and other class M asteroids originate from the metallic core of a large differentiated planetesimal similar to asteroid 4 Vesta.
Psyche is massive enough that its perturbations on other asteroids can be measured, which enables accurate mass and density values. Its density turns out to be extremely low, indicating extreme porousity or (less likely) a non-metallic composition. In other words, the asteroid is probably a gigantic rubble pile. (1) (http://homepage.mac.com/brother_guy/.cv/brother_guy/Public/Asteroid%20Densities.pdf-link.pdf)
Only one stellar occultation event by Psyche has so far been observed (from Mexico on March 22, 2002). Lightcurve variations indicate a non-spherical body.
| The Minor Planets |
| Vulcanoids | Main belt | Groups and Families | Near-Earth objects | Jupiter Trojans |
| Centaurs | Trans-Neptunians | Damocloids | Comets | Kuiper Belt | Oort Cloud |
| (For other objects and regions, see: Binary asteroids, Asteroid moons and the Solar system) |
| (For a complete listing, see: List of asteroids) |
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