54_Alexandra

54 Alexandra

54 Alexandra

Main-belt asteroid

Alexandra (minor planet designation: 54 Alexandra) is a carbonaceous asteroid from the intermediate asteroid belt, approximately 155 kilometers in diameter. It was discovered by German-French astronomer Hermann Goldschmidt on 10 September 1858, and named after the German explorer Alexander von Humboldt; it was the first asteroid to be named after a male.[7]

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Description

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).[8] The mass of the asteroid can be estimated based upon the mutually perturbing effects of other bodies, yielding an estimate of (6.16±3.50)×1018 kg.[3]

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.[4] Alexandra has been studied by radar.[9] 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.[10] 145 Adeona was subsequently assigned to the Adeona family, with Alexandra and Panopaea being dropped.[11]

In the Swedish film Aniara (2018) it is mentioned that 54 Alexandra is the closest celestial body which the off-course and out-of-control spacecraft will approach before it leaves the Solar System.

References

  1. [1]
    Yeomans, Donald K. "54 Alexandra". JPL Small-Body Database Browser. NASA Jet Propulsion Laboratory. Retrieved 7 April 2013.
  2. [2]
    "Alexandra". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 22 March 2020.
    "Alexandra". Dictionary.com Unabridged (Online). n.d.
  3. [3]
    Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
  4. [4]
    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, vol. 101, no. 3, pp. 507–511, Bibcode:1993A&AS..101..507B.
  5. [5]
    Hanuš, J.; et al. (May 2017), "Volumes and bulk densities of forty asteroids from ADAM shape modeling", Astronomy & Astrophysics, 601: 41, arXiv:1702.01996, Bibcode:2017A&A...601A.114H, doi:10.1051/0004-6361/201629956, A114.
  6. [6]
    "Asteroid Data Sets". Archived from the original on 17 December 2009. Retrieved 12 January 2007.
  7. [7]
    Schmadel, Lutz D. (2003), Dictionary of Minor Planet Names (5th ed.), Springer, p. 20, ISBN 3642297188.
  8. [8]
    D.W. Dunham, "Upcoming Asteroid Occultations", Sky & Telescope, June, 2006, p. 63.
  9. [9]
    "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. Retrieved 30 October 2011.
  10. [10]
    Williams, J. G. (March 1988), "The Unusual Alexandra Family", Abstracts of the Lunar and Planetary Science Conference, vol. 19, pp. 1277–1278, Bibcode:1988LPI....19.1277W.
  11. [11]
    Zappala, Vincenzo; et al. (December 1990), "Asteroid families. I - Identification by hierarchical clustering and reliability assessment", Astronomical Journal, vol. 100, pp. 2030–2046, 2045, Bibcode:1990AJ....100.2030Z, doi:10.1086/115658. See p. 2045 and family 44.
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