54 Alexandra
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Discovery[1]
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| Discovered by | Hermann Mayer Salomon Goldschmidt |
| Discovery date | September 10, 1858 |
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Designations
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| Named after | Alexander von Humboldt |
| Alternate name(s) | |
| Minor planet category |
Main belt |
| Epoch December 31, 2006 (JD 2454100.5) | |
| Aphelion | 485.483 Gm (3.245 AU) |
| Perihelion | 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) |
| Average orbital speed | 17.91 km/s |
| Mean anomaly | 103.809° |
| Inclination | 11.804° |
| Longitude of ascending node | 313.446° |
| Argument of perihelion | 345.594° |
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Physical characteristics
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| Dimensions | 165.8 km[1] |
| Mass | ~5×1018 kg (assumed) |
| Mean density | ? g/cm³ |
| Equatorial surface gravity | 0.0463 m/s² |
| Escape velocity | 0.0877 km/s |
| Rotation period | ? d |
| Albedo | 0.056[1][2] |
| Temperature | ~169 K |
| Spectral type | C[1] |
| Absolute magnitude (H) | 7.66[1] |
54 Alexandra is a very large and dark main-belt asteroid. It was discovered by Hermann Goldschmidt on September 10, 1858, and named after the German explorer Alexander von Humboldt; it was the first asteroid to be named after a male.[3]
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).[4]
Alexandra has been studied by radar.[5]
[edit] Notes and references
- ^ a b c d e "JPL Small-Body Database Browser: 54 Alexandra". Jet Propulsion Laboratory. 2011-12-30 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=54. Retrieved 2012-01-23.
- ^ Asteroid Data Sets
- ^ Lutz D. Schmadel, Dictionary of Minor Planet Names, p.20.
- ^ D.W. Dunham, "Upcoming Asteroid Occultations", Sky & Telescope, June, 2006, p. 63.
- ^ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. http://echo.jpl.nasa.gov/asteroids/. Retrieved 2011-10-30.
[edit] External links
- Orbital simulation from JPL (Java) / Ephemeris
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This article about a C-type asteroid native to the main belt is a stub. You can help Wikipedia by expanding it. |
