54 Alexandra

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54 Alexandra
54Alexandra (Lightcurve Inversion).png
A three-dimensional model of 54 Alexandra based on its light curve.
Discovery[1]
Discovered by Hermann Mayer Salomon Goldschmidt
Discovery date September 10, 1858
Designations
Named after
Alexander von Humboldt
Main belt
Orbital characteristics
Epoch December 31, 2006 (JD 2454100.5)
Aphelion 485.483 Gm (3.245 AU)
Perihelion 326.043 Gm (2.179 AU)
405.763 Gm (2.712 AU)
Eccentricity 0.196
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17.91 km/s
103.809°
Inclination 11.804°
313.446°
345.594°
Physical characteristics
Dimensions 165.8[1] km
Mass (6.16 ± 3.50) × 1018[2] kg
Mean density
3.50 ± 2.11[2] g/cm3
0.0463 m/s²
0.0877 km/s
18.14[3] h
Albedo 0.056[1][4]
Temperature ~169 K
Spectral type
C[1]
7.66[1]

54 Alexandra is a very large and dark main-belt asteroid. It was discovered by German-French astronomer 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.[5]

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).[6]

Photometric observations of this asteroid during 1990–92 gave a light curve with a period of 18.14 ± 0.04 hours and a brightness variation of 0.10 in magnitude.[3] Alexandra has been studied by radar.[7] It was the namesake and largest member of the former Alexandra asteroid family; a dynamic group of C-type asteroids that share similar orbital elements. Other members included 70 Panopaea and 145 Adeona.[8] 145 Adeona was subsequently assigned to the Adeona family, with Alexandra and Panopaea being dropped.[9]

References

  1. 1.0 1.1 1.2 1.3 1.4 Lua error in package.lua at line 80: module 'strict' not found.
  2. 2.0 2.1 Lua error in package.lua at line 80: module 'strict' not found. See Table 1.
  3. 3.0 3.1 Lua error in package.lua at line 80: module 'strict' not found.
  4. Asteroid Data Sets
  5. Lua error in package.lua at line 80: module 'strict' not found.
  6. D.W. Dunham, "Upcoming Asteroid Occultations", Sky & Telescope, June, 2006, p. 63.
  7. Lua error in package.lua at line 80: module 'strict' not found.
  8. Lua error in package.lua at line 80: module 'strict' not found.
  9. Lua error in package.lua at line 80: module 'strict' not found. See p. 2045 and family 44.

External links


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