Astronomy:4217 Engelhardt

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4217 Engelhardt
Discovery [1]
Discovered byC. Shoemaker
Discovery sitePalomar Obs.
Discovery date24 January 1988
Designations
(4217) Engelhardt
Named afterWolf von Engelhardt
(German mineralogist)[2]
1988 BO2 · 1944 RL
1951 RY1 · 1970 AA
Minor planet categorymain-belt · Phocaea[3][4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc72.73 yr (26,563 days)
|{{{apsis}}}|helion}}2.8045 AU
|{{{apsis}}}|helion}}1.8246 AU
2.3145 AU
Eccentricity0.2117
Orbital period3.52 yr (1,286 days)
Mean anomaly272.23°
Mean motion0° 16m 47.64s / day
Inclination23.129°
Longitude of ascending node355.44°
348.79°
Known satellites1 (P: 36.03 h)[5][lower-alpha 1]
Physical characteristics
Dimensions7.34±1.36 km[6]
8.742±0.356 km[7][8]
9.16±1.0 km[9]
9.24 km (derived)[3]
Rotation period3.066±0.001 h[10]
3.0661±0.0002 h[5][lower-alpha 1]
Geometric albedo0.2108±0.052[9]
0.231±0.046[7][8]
0.2489 (derived)[3]
0.37±0.17[6]
S[3][11]
Absolute magnitude (H)12.10±0.67[11] · 12.20[6] · 12.3[1][3] · 12.50[7][9]


4217 Engelhardt, provisional designation 1988 BO2, 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.[12]

Classification and orbit

Engelhardt is a stony S-type asteroid and a member of the Phocaea family (701).[4] 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.[1]

It was first identified as 1944 RL at Turku Observatory in 1944, extending the body's observation arc by 44 years prior to its official discovery observation at Palomar.[12] It will pass about 0.0017 AU (250,000 km) from Earth threatening asteroid (29075) 1950 DA in 2736.[13]

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.[lower-alpha 1] Lightcurve analysis gave a well-defined rotation period of 3.066 hours with a brightness amplitude of 0.16 magnitude ({{{1}}}).[10]

In December 2011, a follow-up observation by Warner gave a period of 3.0661 hours with 0.18 amplitude ({{{1}}}).[5] 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.[lower-alpha 1]

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.[7] 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.[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.[2] The approved naming citation was published by the Minor Planet Center on 27 June 1991 (M.P.C. 18456).[14]

Notes

  1. 1.0 1.1 1.2 1.3 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

  1. 1.0 1.1 1.2 1.3 "JPL Small-Body Database Browser: 4217 Engelhardt (1988 BO2)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004217. 
  2. 2.0 2.1 Schmadel, Lutz D. (2007). "(4217) Engelhardt". Dictionary of Minor Planet Names – (4217) Engelhardt. Springer Berlin Heidelberg. p. 361. doi:10.1007/978-3-540-29925-7_4182. ISBN 978-3-540-00238-3. 
  3. 3.0 3.1 3.2 3.3 3.4 3.5 "LCDB Data for (4217) Engelhardt". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=4217%7CEngelhardt. 
  4. 4.0 4.1 "Asteroid 4217 Engelhardt – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=4217+Engelhardt#Asteroid%204217%20EngelhardtEAR-A-VARGBDET-5-NESVORNYFAM-V3.0. 
  5. 5.0 5.1 5.2 Warner, Brian D. (April 2012). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2011 September - December". The Minor Planet Bulletin 39 (2): 69–80. ISSN 1052-8091. Bibcode2012MPBu...39...69W. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012MPBu...39...69W. Retrieved 4 April 2017. 
  6. 6.0 6.1 6.2 Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T. et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal 814 (2): 13. doi:10.1088/0004-637X/814/2/117. Bibcode2015ApJ...814..117N. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015ApJ...814..117N. Retrieved 4 April 2017. 
  7. 7.0 7.1 7.2 7.3 Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D. et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal 741 (2): 25. doi:10.1088/0004-637X/741/2/90. Bibcode2011ApJ...741...90M. 
  8. 8.0 8.1 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J. et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal 741 (2): 20. doi:10.1088/0004-637X/741/2/68. Bibcode2011ApJ...741...68M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...68M. Retrieved 4 April 2017. 
  9. 9.0 9.1 9.2 Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode2004PDSS...12.....T. https://sbnarchive.psi.edu/pds3/iras/IRAS_A_FPA_3_RDR_IMPS_V6_0/data/diamalb.tab. Retrieved 22 October 2019. 
  10. 10.0 10.1 Warner, Brian D. (June 2005). "Asteroid lightcurve analysis at the Palmer Divide Observatory - fall 2004". The Minor Planet Bulletin 32 (2): 29–32. ISSN 1052-8091. Bibcode2005MPBu...32...29W. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2005MPBu...32...29W. Retrieved 4 April 2017. 
  11. 11.0 11.1 Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus 261: 34–47. doi:10.1016/j.icarus.2015.08.007. Bibcode2015Icar..261...34V. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V. Retrieved 4 April 2017. 
  12. 12.0 12.1 "4217 Engelhardt (1988 BO2)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=4217. 
  13. Giorgini, J. D.; Ostro, S. J.; Benner, L. A. M.; Chodas, P. W.; Chesley, S. R.; Hudson, R. S. et al. (April 2002). "Asteroid 1950 DA's Encounter with Earth in 2880: Physical Limits of Collision Probability Prediction". Science 296 (5565): 132–136. doi:10.1126/science.1068191. PMID 11935024. Bibcode2002Sci...296..132G. http://neo.jpl.nasa.gov/1950da/1950da.pdf. Retrieved 4 April 2017. 
  14. "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html. 

External links