Astronomy:54 Alexandra
.png) A three-dimensional model of 54 Alexandra based on its light curve | |
| Discovery[1] | |
|---|---|
| Discovered by | H. Goldschmidt |
| Discovery date | 10 September 1858 |
| Designations | |
| (54) Alexandra | |
| Pronunciation | /ˌælɪɡˈzændrə, -ˈzɑːn-/ AL-ig-ZA(H)N-drə[2] |
| Named after | Alexander von Humboldt (German explorer) |
| Minor planet category | Main belt |
| Adjectives | Alexandrian |
| Orbital characteristics | |
| Epoch December 31, 2006 (JD 2454100.5) | |
| |{{{apsis}}}|helion}} | 485.483 Gm (3.245 AU) |
| |{{{apsis}}}|helion}} | 326.043 Gm (2.179 AU) |
| 405.763 Gm (2.712 AU) | |
| Eccentricity | 0.196 |
| Orbital period | 1,631.620 d (4.47 a) |
| Mean anomaly | 103.809° |
| Inclination | 11.804° |
| Longitude of ascending node | 313.446° |
| 345.594° | |
| Physical characteristics | |
| Dimensions | 160 × 135 km (± 1 km) |
| Mean diameter | 154.137 km[1] |
| Mass | (6.16±3.50)×1018 kg[3] |
| Mean density | 3.50±2.11 g/cm3[3] |
| Rotation period | 18.14 h[4] |
| Pole ecliptic latitude | 155°±4°[5] |
| Pole ecliptic longitude | 17°±3°[5] |
| Geometric albedo | 0.056[1][6] |
| Tholen = C [1] SMASS = C [1] | |
| Absolute magnitude (H) | 7.66[1] |
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]
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 United States 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 Popular Culture
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
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Yeomans, Donald K.. "54 Alexandra". JPL Small-Body Database Browser. NASA Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=54.
- ↑ "Alexandra". Alexandra. Oxford University Press. http://www.lexico.com/definition/Alexandra.
"Alexandra". Dictionary.com Unabridged. Random House. https://www.dictionary.com/browse/Alexandra. - ↑ 3.0 3.1 3.2 Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73: pp. 98–118, doi:10.1016/j.pss.2012.03.009, Bibcode: 2012P&SS...73...98C. See Table 1.
- ↑ 4.0 4.1 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.
- ↑ 5.0 5.1 Hanuš, J. et al. (May 2017), "Volumes and bulk densities of forty asteroids from ADAM shape modeling", Astronomy & Astrophysics 601: 41, doi:10.1051/0004-6361/201629956, A114, Bibcode: 2017A&A...601A.114H.
- ↑ "Asteroid Data Sets". http://www.psi.edu/pds/resource/albedo.html.
- ↑ Schmadel, Lutz D. (2003), Dictionary of Minor Planet Names (5th ed.), Springer, p. 20, ISBN 3642297188, https://books.google.com/books?id=KWrB1jPCa8AC&pg=PA20.
- ↑ 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/.
- ↑ 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, doi:10.1086/115658, Bibcode: 1990AJ....100.2030Z. See p. 2045 and family 44.
External links
- Lightcurve plot of 54 Alexandra, Palmer Divide Observatory, B. D. Warner (2008)
- Asteroid Lightcurve Database (LCDB), query form (info )
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- 54 Alexandra at AstDyS-2, Asteroids—Dynamic Site
- 54 Alexandra at the JPL Small-Body Database
 |  |
