4217 Engelhardt
{{Short description|Asteroid}}
{{Use dmy dates|date=October 2019}}
{{Infobox planet
| minorplanet = yes
| name = 4217 Engelhardt
| background = #D6D6D6
| image =
| image_size =
| caption =
| discovered = 24 January 1988
| discoverer = C. Shoemaker
| discovery_site = Palomar Obs.
| mpc_name = (4217) Engelhardt
| alt_names = {{mp|1988 BO|2}}{{·}}1944 RL
{{mp|1951 RY|1}}{{·}}1970 AA
| pronounced =
| named_after = Wolf von Engelhardt
{{small|(German mineralogist)}}
| mp_category = main-belt{{·}}Phocaea
| epoch = 4 September 2017 (JD 2458000.5)
| uncertainty = 0
| observation_arc = 72.73 yr (26,563 days)
| aphelion = 2.8045 AU
| perihelion = 1.8246 AU
| semimajor = 2.3145 AU
| eccentricity = 0.2117
| period = 3.52 yr (1,286 days)
| mean_anomaly = 272.23°
| mean_motion = {{Deg2DMS|0.2799|sup=ms}} / day
| inclination = 23.129°
| asc_node = 355.44°
| arg_peri = 348.79°
| satellites = 1 {{small|(P: 36.03 h)}}{{efn|name=Lightcurve-plot}}
| dimensions = {{val|7.34|1.36}} km
{{val|8.742|0.356}} km
{{val|9.16|1.0}} km
9.24 km {{small|(derived)}}
| rotation = {{val|3.066|0.001}} h
{{val|3.0661|0.0002}} h{{efn|name=Lightcurve-plot}}
| albedo = {{val|0.2108|0.052}}
{{val|0.231|0.046}}
0.2489 {{small|(derived)}}
{{val|0.37|0.17}}
| spectral_type = S
| abs_magnitude = {{val|12.10|0.67}}{{·}}12.20{{·}}12.3{{·}}12.50
}}
4217 Engelhardt, provisional designation {{mp|1988 BO|2}}, is a stony Phocean asteroid and a potentially binary system from the inner regions of the asteroid belt, approximately 9 kilometers in diameter. It was discovered on 24 January 1988, by American astronomer Carolyn Shoemaker at Palomar Observatory in California, and later named after German mineralogist Wolf von Engelhardt.
Classification and orbit
Engelhardt is a stony S-type asteroid and a member of the Phocaea family ({{small|701}}). It orbits the Sun in the inner main-belt at a distance of 1.8–2.8 AU once every 3 years and 6 months (1,286 days). Its orbit has an eccentricity of 0.21 and an inclination of 23° with respect to the ecliptic.
It was first identified as {{mp|1944 RL}} at Turku Observatory in 1944, extending the body's observation arc by 44 years prior to its official discovery observation at Palomar. It will pass about {{convert|0.0017|AU|km|abbr=on|lk=off}} from Earth threatening asteroid {{mpl|(29075) 1950 DA}} in 2736.
Physical characteristics
= Lightcurves =
In November 2004, a rotational lightcurve of Engelhardt was obtained from photometric observations by American astronomer Brian Warner at this Palmer Divide Observatory in Colorado.{{efn|name=Lightcurve-plot}} Lightcurve analysis gave a well-defined rotation period of 3.066 hours with a brightness amplitude of 0.16 magnitude ({{small|U=3}}).
In December 2011, a follow-up observation by Warner gave a period of 3.0661 hours with 0.18 amplitude ({{small|U=3}}). Due to a couple of supposed occultation and eclipsing events, Warner also suspects that Engelhardt might by a binary system with a minor-planet moon orbiting it every 36.03 hours. The result, however, is far from conclusive.{{efn|name=Lightcurve-plot}}
= Diameter and albedo =
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Engelhardt measures between 7.34 and 9.16 kilometers in diameter and its surface has an albedo between and 0.231 and 0.37. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.2489 and a diameter of 9.24 kilometers with on an absolute magnitude of 12.3.
Naming
Baltic German geologist and mineralogist Wolf von Engelhardt (1910–2008), expert on impact craters and related mineral metamorphism. He was a professor at the University of Tübingen and a longtime director of its Institute of Mineralogy and Petrography. The approved naming citation was published by the Minor Planet Center on 27 June 1991 ({{small|M.P.C. 18456}}).
Notes
{{notelist|refs=
{{efn|name=Lightcurve-plot|1=[http://www.minorplanetobserver.com/pdolc/A4217_2011.HTM Lightcurve plot] of (4217) Engelhardt, at the Palmer Divide Observatory, by B. D. Warner (2011). The first plot gives a rotation period of 3.0661 hours. The second plot has that period subtracted and gives a possible orbital period of 36.03 hours for the presumed satellite.}}
}}
References
{{reflist|30em|refs=
|type = 2017-06-05 last obs.
|title = JPL Small-Body Database Browser: 4217 Engelhardt (1988 BO2)
|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004217
|publisher = Jet Propulsion Laboratory
|access-date = 4 July 2017}}
|title = Dictionary of Minor Planet Names – (4217) Engelhardt
|last = Schmadel | first = Lutz D.
|publisher = Springer Berlin Heidelberg
|page = 361
|date = 2007
|isbn = 978-3-540-00238-3
|doi = 10.1007/978-3-540-29925-7_4182 |chapter = (4217) Engelhardt }}
|title = 4217 Engelhardt (1988 BO2)
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=4217
|access-date = 4 April 2017}}
|title = MPC/MPO/MPS Archive
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html
|access-date = 4 April 2017}}
|display-authors = 6
|first1 = Joseph R. |last1 = Masiero
|first2 = A. K. |last2 = Mainzer
|first3 = T. |last3 = Grav
|first4 = J. M. |last4 = Bauer
|first5 = R. M. |last5 = Cutri
|first6 = J. |last6 = Dailey
|first7 = P. R. M. |last7 = Eisenhardt
|first8 = R. S. |last8 = McMillan
|first9 = T. B. |last9 = Spahr
|first10 = M. F. |last10 = Skrutskie
|first11 = D. |last11 = Tholen
|first12 = R. G. |last12 = Walker
|first13 = E. L. |last13 = Wright
|first14 = E. |last14 = DeBaun
|first15 = D. |last15 = Elsbury
|first16 = T. IV |last16 = Gautier
|first17 = S. |last17 = Gomillion
|first18 = A. |last18 = Wilkins
|date = November 2011
|title = Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...68M
|journal = The Astrophysical Journal
|volume = 741
|issue = 2
|page = 20
|bibcode = 2011ApJ...741...68M
|doi = 10.1088/0004-637X/741/2/68
|arxiv = 1109.4096
|access-date= 4 April 2017}}
|display-authors = 6
|first1 = J. D. |last1 = Giorgini
|first2 = S. J. |last2 = Ostro
|first3 = L. A. M. |last3 = Benner
|first4 = P. W. |last4 = Chodas
|first5 = S. R. |last5 = Chesley
|first6 = R. S. |last6 = Hudson
|first7 = M. C. |last7 = Nolan
|first8 = A. R. |last8 = Klemola
|first9 = E. M. |last9 = Standish
|first10 = R. F. |last10 = Jurgens
|first11 = R. |last11 = Rose
|first12 = A. B. |last12 = Chamberlin
|first13 = D. K. |last13 = Yeomans
|first14 = J.-L. |last14 = Margot
|date = April 2002
|title = Asteroid 1950 DA's Encounter with Earth in 2880: Physical Limits of Collision Probability Prediction
|url = http://neo.jpl.nasa.gov/1950da/1950da.pdf
|archive-url = https://web.archive.org/web/20080704103055/http://neo.jpl.nasa.gov/1950da/1950da.pdf
|archive-date = 2008-07-04
|journal = Science
|volume = 296
|issue = 5565
|pages = 132–136
|bibcode = 2002Sci...296..132G
|doi = 10.1126/science.1068191
|pmid = 11935024
|access-date= 4 April 2017}}
|title = Asteroid 4217 Engelhardt – Nesvorny HCM Asteroid Families V3.0
|work = Small Bodies Data Ferret
|url = https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=4217+Engelhardt#Asteroid%204217%20EngelhardtEAR-A-VARGBDET-5-NESVORNYFAM-V3.0
|access-date = 27 October 2019}}
|title = LCDB Data for (4217) Engelhardt
|publisher = Asteroid Lightcurve Database (LCDB)
|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=4217%7CEngelhardt
|access-date = 4 April 2017}}
|first1 = E. F. |last1 = Tedesco
|first2 = P. V. |last2 = Noah
|first3 = M. |last3 = Noah
|first4 = S. D. |last4 = Price
|date = October 2004
|title = IRAS Minor Planet Survey V6.0
|url = https://sbnarchive.psi.edu/pds3/iras/IRAS_A_FPA_3_RDR_IMPS_V6_0/data/diamalb.tab
|journal = NASA Planetary Data System
|volume = 12
|pages = IRAS-A-FPA-3-RDR-IMPS-V6.0
|bibcode = 2004PDSS...12.....T
|access-date= 22 October 2019}}
|display-authors = 6
|first1 = A. |last1 = Mainzer
|first2 = T. |last2 = Grav
|first3 = J. |last3 = Masiero
|first4 = E. |last4 = Hand
|first5 = J. |last5 = Bauer
|first6 = D. |last6 = Tholen
|first7 = R. S. |last7 = McMillan
|first8 = T. |last8 = Spahr
|first9 = R. M. |last9 = Cutri
|first10 = E. |last10 = Wright
|first11 = J. |last11 = Watkins
|first12 = W. |last12 = Mo
|first13 = C. |last13 = Maleszewski
|date = November 2011
|title = NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results
|journal = The Astrophysical Journal
|volume = 741
|issue = 2
|page = 25
|bibcode = 2011ApJ...741...90M
|doi = 10.1088/0004-637X/741/2/90
|arxiv = 1109.6407}}
|display-authors = 6
|first1 = C. R. |last1 = Nugent
|first2 = A. |last2 = Mainzer
|first3 = J. |last3 = Masiero
|first4 = J. |last4 = Bauer
|first5 = R. M. |last5 = Cutri
|first6 = T. |last6 = Grav
|first7 = E. |last7 = Kramer
|first8 = S. |last8 = Sonnett
|first9 = R. |last9 = Stevenson
|first10 = E. L. |last10 = Wright
|date = December 2015
|title = NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015ApJ...814..117N
|journal = The Astrophysical Journal
|volume = 814
|issue = 2
|page = 13
|bibcode = 2015ApJ...814..117N
|doi = 10.1088/0004-637X/814/2/117
|arxiv = 1509.02522
|access-date= 4 April 2017}}
|author = Warner, Brian D.
|date = June 2005
|title = Asteroid lightcurve analysis at the Palmer Divide Observatory - fall 2004
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2005MPBu...32...29W
|journal = The Minor Planet Bulletin
|volume = 32
|issue = 2
|pages = 29–32
|issn = 1052-8091
|bibcode = 2005MPBu...32...29W
|access-date= 4 April 2017}}
|author = Warner, Brian D.
|date = April 2012
|title = Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2011 September - December
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012MPBu...39...69W
|journal = The Minor Planet Bulletin
|volume = 39
|issue = 2
|pages = 69–80
|issn = 1052-8091
|bibcode = 2012MPBu...39...69W
|access-date= 4 April 2017}}
|display-authors = 6
|first1 = Peter |last1 = Veres
|first2 = Robert |last2 = Jedicke
|first3 = Alan |last3 = Fitzsimmons
|first4 = Larry |last4 = Denneau
|first5 = Mikael |last5 = Granvik
|first6 = Bryce |last6 = Bolin
|first7 = Serge |last7 = Chastel
|first8 = Richard J. |last8 = Wainscoat
|first9 = William S. |last9 = Burgett
|first10 = Kenneth C. |last10 = Chambers
|first11 = Heather |last11 = Flewelling
|first12 = Nick |last12 = Kaiser
|first13 = Eugen A. |last13 = Magnier
|first14 = Jeff S. |last14 = Morgan
|first15 = Paul A. |last15 = Price
|first16 = John L. |last16 = Tonry
|first17 = Christopher |last17 = Waters
|date = November 2015
|title = Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V
|journal = Icarus
|volume = 261
|pages = 34–47
|bibcode = 2015Icar..261...34V
|doi = 10.1016/j.icarus.2015.08.007
|arxiv = 1506.00762
|access-date= 4 April 2017}}
}}
External links
- [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|4217}}
- {{JPL small body}}
{{Minor planets navigator |4216 Neunkirchen |number=4217 |4218 Demottoni}}
{{Small Solar System bodies}}
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