54 Alexandra
|
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 |
| 1,631.620 d (4.47 a) | |
Average orbital speed | 17.91 km/s |
| 103.809° | |
| Inclination | 11.804° |
| 313.446° | |
| 345.594° | |
| Physical characteristics | |
| Dimensions | 165.8 km[1] |
| Mass | (6.16 ± 3.50) × 1018 kg[2] |
Mean density | 3.50 ± 2.11 g/cm3[2] |
| 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] | |
|
| |
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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 2 3 4 5 Yeomans, Donald K. "54 Alexandra". JPL Small-Body Database Browser. NASA Jet Propulsion Laboratory. Retrieved 2013-04-07.
- 1 2 Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73, pp. 98–118, arXiv:1203.4336
, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1. - 1 2 Belskaya, I. N.; et al. (November 1993), "Physical Studies of Asteroids. Part XXVII. Photoelectric Photometry of Asteroids 14 Irene, 54 Alexandra and 56 Melete", Astronomy and Astrophysics Supplement, 101 (3), pp. 507–511, Bibcode:1993A&AS..101..507B.
- ↑ Asteroid Data Sets
- ↑ Schmadel, Lutz D. (2003), Dictionary of Minor Planet Names (5th ed.), Springer, p. 20, ISBN 3642297188.
- ↑ D.W. Dunham, "Upcoming Asteroid Occultations", Sky & Telescope, June, 2006, p. 63.
- ↑ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. Retrieved 2011-10-30.
- ↑ Williams, J. G. (March 1988), "The Unusual Alexandra Family", Abstracts of the Lunar and Planetary Science Conference, 19, pp. 1277–1278, Bibcode:1988LPI....19.1277W.
- ↑ Zappala, Vincenzo; et al. (December 1990), "Asteroid families. I - Identification by hierarchical clustering and reliability assessment", Astronomical Journal, 100, pp. 2030–2046, 2045, Bibcode:1990AJ....100.2030Z, doi:10.1086/115658. See p. 2045 and family 44.
