21 Lutetia
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| Discovery A (http://cfa-www.harvard.edu/iau/lists/NumberedMPs.html) | |
|---|---|
| Discoverer | Hermann M. S. Goldschmidt |
| Discovery date | November 15, 1852 |
| Alternate designations | B (http://cfa-www.harvard.edu/iau/MPDes.html) |
| Category | Main belt |
| Orbital elements C (http://asteroid.lowell.edu/) Epoch January 30, 2005 (JD 2453400.5) | |
| Eccentricity (e) | 0.164 |
| Semi-major axis (a) | 364.277 Gm (2.435 AU) |
| Perihelion (q) | 304.600 Gm (2.036 AU) |
| Aphelion (Q) | 423.955 Gm (2.834 AU) |
| Orbital period (P) | 1387.902 d (3.80 a) |
| Mean orbital speed | 18.96 km/s |
| Inclination (i) | 3.064° |
| Longitude of the ascending node (Ω) | 80.917° |
| Argument of perihelion (ω) | 250.227° |
| Mean anomaly (M) | 75.393° |
| Physical characteristics | |
| Dimensions | 95.8 km |
| Mass | 9.2×1017 kg |
| Density | 2.0 g/cm³ |
| Surface gravity | 0.0268 m/s² |
| Escape velocity | 0.0506 km/s |
| Rotation period | 0.3405 d (8.172 h) 3 (http://www.psi.edu/pds/archive/lc.html) |
| Spectral class | M |
| Absolute magnitude | 7.35 |
| Albedo | 0.221 4 (http://dorothy.as.arizona.edu/DSN/IRAS/index_iras.html) |
| Mean surface temperature | ~183 K |
21 Lutetia (lew-tee'-sha) is a large Main belt asteroid, about 100 kilometers in diameter.
It was discovered on November 15, 1852 by Hermann Mayer Salomon Goldschmidt at the observatory of Paris. The name Lutetia derives from the Latin name of Paris.
On July 10, 2010 the European Rosetta comet probe will pass the asteroid with a minimum distance of 3000 km on its way to 67P/Churyumov-Gerasimenko.
It will be a rather important flyby, since Lutetia is not only large but also the first metallic M-type asteroid to be visited by a spacecraft. There are serious questions about the metallicity of the M-type asteroids and the probe is expected to settle the issue.
There are two reported stellar occultations by Lutetia: from Malta (1997) and Australia (2003).
| 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. For pronunciation, see: Pronunciation of asteroid names.) |