54 Alexandra
{{Short description|Main-belt asteroid}}
{{Use dmy dates|date=July 2018}}
{{Infobox planet
| minorplanet=yes
| background=#D6D6D6
| name=54 Alexandra
| image=54Alexandra (Lightcurve Inversion).png
| image_scale =
| caption=A three-dimensional model of 54 Alexandra based on its light curve
| discoverer=H. Goldschmidt
| discovered= 10 September 1858
| mpc_name=(54) Alexandra
| alt_names=
| pronounced={{IPAc-en|ˌ|æ|l|ᵻ|g|'|z|æ|n|d|r|ə|,_|-|'|z|ɑː|n|-}} {{respell|AL|ig|ZA(H)N|drə}}{{Cite encyclopedia |url=http://www.lexico.com/definition/Alexandra |archive-url=https://web.archive.org/web/20200322182812/https://www.lexico.com/definition/alexandra |url-status=dead |archive-date=22 March 2020 |title=Alexandra |dictionary=Lexico UK English Dictionary |publisher=Oxford University Press}}
{{dict.com|Alexandra}}
| adjective=Alexandrian
| named_after = {{nowrap|Alexander von Humboldt}}
{{small|(German explorer)}}
| mp_category=Main belt
| epoch=December 31, 2006 (JD 2454100.5)
| semimajor={{nowrap|405.763 Gm (2.712 AU)}}
| perihelion={{nowrap|326.043 Gm (2.179 AU)}}
| aphelion={{nowrap|485.483 Gm (3.245 AU)}}
| eccentricity=0.196
| period={{Convert|1631.620|day|year|sigfig=3|abbr=on|lk=out}}
| inclination=11.804°
| asc_node=313.446°
| arg_peri=345.594°
| pole_ecliptic_lat={{Val|155|4|u=°}}
| pole_ecliptic_lon={{Val|17|3|u=°}}
| mean_anomaly=103.809°
| dimensions = 160 × 135 km (± 1 km)
| mass={{val|6.16|3.50|e=18|u=kg}}
| density={{val|3.50|2.11|u=g/cm3}}
| rotation=18.14 h
| spectral_type=Tholen {{=}} C
SMASS {{=}} C
| albedo=0.056{{Cite web |url=http://www.psi.edu/pds/resource/albedo.html |title=Asteroid Data Sets |access-date=12 January 2007 |archive-date=17 December 2009 |archive-url=https://web.archive.org/web/20091217104722/http://www.psi.edu/pds/resource/albedo.html |url-status=dead }}
}}
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.
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).D.W. Dunham, "Upcoming Asteroid Occultations", Sky & Telescope, June, 2006, p. 63. The mass of the asteroid can be estimated based upon the mutually perturbing effects of other bodies, yielding an estimate of {{Val|6.16|3.50|e=18|u=kg}}.
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. Alexandra has been studied by radar. 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. 145 Adeona was subsequently assigned to the Adeona family, with Alexandra and Panopaea being dropped.
In popular culture
In the Swedish film Aniara, 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
{{Reflist|refs=
| first1 = Donald K.
| last1 = Yeomans
| title = 54 Alexandra
| work = JPL Small-Body Database Browser
| publisher = NASA Jet Propulsion Laboratory
| url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=54
| access-date= 2013-04-07
}}
| title=Volumes and bulk densities of forty asteroids from ADAM shape modeling
| last1=Hanuš | first1=J. | last2=Viikinkoski | first2=M.
| last3=Marchis | first3=F. | last4=Ďurech | first4=J.
| last5=Kaasalainen | first5=M. | last6=Delbo' | first6=M.
| last7=Herald | first7=D. | last8=Frappa | first8=E.
| last9=Hayamizu | first9=T. | last10=Kerr | first10=S.
| last11=Preston | first11=S. | last12=Timerson | first12=B.
| last13=Dunham | first13=D. | last14=Talbot | first14=J.
| journal=Astronomy & Astrophysics | display-authors=1
| volume=601 | id=A114 | pages=41 | date=May 2017
| doi=10.1051/0004-6361/201629956 | bibcode=2017A&A...601A.114H | arxiv=1702.01996}}
| first1 = Lutz D.
| last1 = Schmadel
| title = Dictionary of Minor Planet Names
| publisher = Springer
| edition = 5th
| page = 20
| date = 2003
| isbn = 3642297188
| url = https://books.google.com/books?id=KWrB1jPCa8AC&pg=PA20
| postscript= .}}
| first1 = B.
| last1 = Carry
| title = Density of asteroids
| work = Planetary and Space Science
| volume = 73
| pages = 98–118
|date=December 2012
| doi = 10.1016/j.pss.2012.03.009
| bibcode = 2012P&SS...73...98C
| postscript= .
|arxiv = 1203.4336 }} See Table 1.
| last1 = Belskaya
| first1 = I. N.
| last2 = Dovgopol
| first2 = A. N.
| last3 = Erikson
| first3 = A.
| last4 = Lagerkvist
| first4 = C.-I.
| last5 = Oja
| first5 = T.
| display-authors = 1
| title = Physical Studies of Asteroids. Part XXVII. Photoelectric Photometry of Asteroids 14 Irene, 54 Alexandra and 56 Melete
| work = Astronomy and Astrophysics Supplement
| volume = 101
| issue = 3
| pages = 507–511
|date=November 1993
| bibcode = 1993A&AS..101..507B
| postscript= .}}
| first1 = J. G.
| last1 = Williams
| title = The Unusual Alexandra Family
| work = Abstracts of the Lunar and Planetary Science Conference
| volume = 19
| pages = 1277–1278
|date=March 1988
| bibcode = 1988LPI....19.1277W
| postscript= .}}
| last1 = Zappala
| first1 = Vincenzo
| last2 = Cellino
| first2 = Alberto
| last3 = Farinella
| first3 = Paolo
| last4 = Knezevic
| first4 = Zoran
| display-authors = 1
| title = Asteroid families. I - Identification by hierarchical clustering and reliability assessment
| work = Astronomical Journal
| volume = 100
| pages = 2030–2046, 2045
|date=December 1990
| doi = 10.1086/115658
| bibcode = 1990AJ....100.2030Z
| postscript= .
| doi-access= free
}} See p. 2045 and family 44.
| title=Radar-Detected Asteroids and Comets
| publisher=NASA/JPL Asteroid Radar Research
| url=http://echo.jpl.nasa.gov/asteroids/
| access-date=2011-10-30}}
}}
External links
- [http://www.minorplanetobserver.com/pdolc/A54_2008.HTM Lightcurve plot of 54 Alexandra], Palmer Divide Observatory, B. D. Warner (2008)
- [http://www.minorplanet.info/PHP/lcdbsummaryquery.php Asteroid Lightcurve Database (LCDB)], query form ([http://www.minorplanet.info/lightcurvedatabase.html info] {{Webarchive|url=https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html |date=16 December 2017 }})
- [https://books.google.com/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books
- [http://obswww.unige.ch/~behrend/page_cou.html Asteroids and comets rotation curves, CdR] – Observatoire de Genève, Raoul Behrend
- [https://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center
- {{AstDys|54}}
- {{JPL small body}}
{{Minor planets navigator |53 Kalypso |number=54 |55 Pandora}}
{{Small Solar System bodies}}
{{Authority control}}
{{DEFAULTSORT:Alexandra}}