54 Alexandra
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| Discovery | |
|---|---|
| Discovered by: | Hermann Mayer Salomon Goldschmidt |
| Discovery date: | September 10, 1858 |
| Alternative names: | |
| Minor planet category: | Main belt |
| Orbital characteristics | |
| Epoch December 31, 2006 (JD 2454100.5) | |
| Aphelion distance: | 485.483 Gm (3.245 AU) |
| Perihelion distance: | 326.043 Gm (2.179 AU) |
| Semi-major axis: | 405.763 Gm (2.712 AU) |
| Eccentricity: | 0.196 |
| Orbital period: | 1631.620 d (4.47 a) |
| Avg. orbital speed: | 17.91 km/s |
| Mean anomaly: | 103.809° |
| Inclination: | 11.804° |
| Longitude of ascending node: | 313.446° |
| Argument of perihelion: | 345.594° |
| Physical characteristics | |
| Dimensions: | 165.8 km |
| Mass: | 4.8×1018 kg |
| Mean density: | ? g/cm³ |
| Equatorial surface gravity: | 0.0463 m/s² |
| Escape velocity: | 0.0877 km/s |
| Rotation period: | ? d |
| Albedo: | 0.056 [1] |
| Temperature: | ~169 K |
| Spectral type: | C |
| Absolute magnitude: | 7.66 |
54 Alexandra is a very large and dark main belt asteroid. It was discovered by H. Goldschmidt on September 10, 1858 and named after the German explorer Alexander von Humboldt. On May 17, 2005 this asteroid occulted a faint star (magnitude 8.5) and the event was observed and timed in a number of locations within the U.S. and Mexico. As a result a silhouette profile was produced, yielding a roughly oval cross-section with dimensions of 160 × 135 km (± 1 km).[2]
[edit] Aspects
[edit] Notes and references
- ^ http://www.psi.edu/pds/resource/albedo.html
- ^ D.W. Dunham, "Upcoming Asteroid Occultations", Sky & Telescope, June, 2006, p. 63.
| Minor planets | ||
|---|---|---|
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| List of asteroids | ||
Vulcanoids · Near-Earth asteroids · Main belt · Jupiter Trojans · Centaurs · Damocloids · Comets · Trans-Neptunians (Kuiper belt • Scattered disc • Oort cloud)
For other objects and regions, see Asteroid groups and families, Binary asteroids, Asteroid moons and the Solar System.
For a complete listing, see List of asteroids. See also Pronunciation of asteroid names and Meanings of asteroid names.
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