216 Kleopatra

216 Kleopatra

3D model of Kleopatra from radar observation (animation)
Discovery [1][2]
Discovered by J. Palisa
Discovery site Pola Obs. (538)
Discovery date 10 April 1880
Designations
MPC designation (216) Kleopatra
Pronunciation (/ˌkliːəˈpætrə, -ˈpɑː-, -ˈpeɪ-/[3])
Named after
 Cleopatra
(Egyptian queen)[4]
A905 OA · A910 RA
main-belt · (central) [5]
Orbital characteristics [1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc 136.42 yr (49,826 days)
Aphelion 3.4936 AU
Perihelion 2.0929 AU
2.7933 AU
Eccentricity 0.2507
4.67 yr (1,705 days)
261.75°
0° 12m 39.96s / day
Inclination 13.114°
215.36°
180.16°
Known satellites 2 (Alexhelios · Cleoselene)
Physical characteristics
Dimensions 217 × 94 × 81 km[6]
124 km[1]
104.3 km[7]
135.07±2.1 km(IRAS:19)[8]
121.55±1.60 km[9]
138.000±19.37 km[10]
137.794 km[11]
102.93±3.81 km[12]
137.79 km (taken)[5]
Mass (4.64±0.02)×1018 kg[13]
Mean density
 4.27 ± 0.86 g/cm3[14]
5.394 h[15][16]
5.386 h[17]
5.385 h[18]
5.38527 h[19]
5.399 h[20]
5.38528 h[21][22][23][24]
5.385263 h[25]
5.38529 h[26]
5.385277 h[27]
5.386±0.003 h[28]
5.376±0.006 h[29]
5.379±0.002 h[30]
5.38±0.05 h[29]
5.3848±0.0003 h[29]
5.386±0.001 h[5][31]
5.39±0.05 h[29]
5.41±0.05 h[32]
5.385414±0.000006 h[29]
0.1164±0.004 (IRAS:19)[1][8]
0.170[7]
0.149±0.005[9]
0.1111±0.0336[10]
0.1068[11]
0.200±0.028[12]
M (Tholen),[1] Xe (SMASS)[1]
M [10][33] · X [5]
B–V = 0.713[1]
U–B = 0.238[1]
7.30[1][8][9][10][12] · 7.35±0.02[5][11][34] · 7.45[7]

    216 Kleopatra (/ˌkliːəˈpætrə, -ˈpɑː-, -ˈpeɪ-/) is a metallic, ham-bone-shaped asteroid and trinary system orbiting in the central region of the asteroid belt, approximately 138 kilometers in diameter (mean). It was discovered on 10 April 1880, by Austrian astronomer Johann Palisa at Pola Observatory, in what is now Pula, Croatia.[2][35] It is named after Cleopatra, the famous Egyptian queen. Two small minor-planet moons were discovered in 2008, and later named Alexhelios and Cleoselene.

    Physical characteristics

    Kleopatra is a relatively large asteroid, measuring 217 × 94 × 81 km.[6] Calculations from its radar albedo and the orbits of its moons show it to be a rubble pile, a loose amalgam of metal, rock, and 30–50% empty space by volume, likely due to a disruptive impact prior to the impact that created its moons.

    Kleopatra has an unusual shape. Initial observations with the ESO 3.6 m Telescope at La Silla, run by the European Southern Observatory, were interpreted to show a double source with two distinct lobes of similar size.[36] These results were disputed when radar observations at the Arecibo Observatory showed that the two lobes of the asteroid are connected, resembling the shape of a ham-bone. The radar observations provided a detailed shape model that appeared on the cover of Science Magazine.[6]

    Moons

    In 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty.[37] In September 2008, Franck Marchis and his collaborators announced that by using the Keck Observatory's adaptive optics system, they had discovered two moons orbiting Kleopatra.[38] The outer and inner satellites are about 5 km and 3 km in diameter, respectively.[39]

    In February 2011, the minor-planet moons were named Alexhelios (/ˌælᵻksˈhiːlioʊs/, outer) and Cleoselene (/ˌkliːoʊsᵻˈliːniː/, inner), after Cleopatra's children Alexander Helios and Cleopatra Selene II.[40]

    Origin

    It is believed that Kleopatra's shape, rotation, and moons are due to an oblique impact perhaps 100 million years ago. The increased rotation would have elongated the asteroid and caused Alexhelios to split off. Cleoselene may have split off later, around 10 million years ago. Kleopatra is a contact binary – if it were spinning much faster, the two lobes would separate from each other, making a true binary system.[13]

    References

    1. 1 2 3 4 5 6 7 8 9 "JPL Small-Body Database Browser: 216 Kleopatra" (2016-09-20 last obs.). Jet Propulsion Laboratory. Retrieved 22 April 2017.
    2. 1 2 "216 Kleopatra". Minor Planet Center. Retrieved 22 April 2017.
    3. ↑ "Kleopatra". Dictionary.com Unabridged. Random House. Retrieved 2016-01-23.
    4. ↑ Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (216) Kleopatra. Springer Berlin Heidelberg. p. 34. ISBN 978-3-540-00238-3. Retrieved 22 April 2017.
    5. 1 2 3 4 5 "LCDB Data for (216) Kleopatra". Asteroid Lightcurve Database (LCDB). Retrieved 22 April 2017.
    6. 1 2 3 Ostro, S. J.; et al. (2000). "Radar Observations of Asteroid 216 Kleopatra". Science. 288 (5467): 836–839. Bibcode:2000Sci...288..836O. ISSN 0036-8075. PMID 10797000. doi:10.1126/science.288.5467.836.
    7. 1 2 3 Shevchenko, Vasilij G.; Tedesco, Edward F. (September 2006). "Asteroid albedos deduced from stellar occultations". Icarus. 184 (1): 211–220. Bibcode:2006Icar..184..211S. doi:10.1016/j.icarus.2006.04.006. Retrieved 22 April 2017.
    8. 1 2 3 Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. Bibcode:2004PDSS...12.....T. Retrieved 22 April 2017.
    9. 1 2 3 Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey" (PDF). Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 22 April 2017.
    10. 1 2 3 4 Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results" (PDF). The Astrophysical Journal. 741 (2): 25. Bibcode:2011ApJ...741...90M. arXiv:1109.6407 Freely accessible. doi:10.1088/0004-637X/741/2/90. Retrieved 22 April 2017.
    11. 1 2 3 Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026. Retrieved 22 April 2017.
    12. 1 2 3 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. Bibcode:2012ApJ...759L...8M. arXiv:1209.5794 Freely accessible. doi:10.1088/2041-8205/759/1/L8. Retrieved 22 April 2017.
    13. 1 2 Marchis, Descamps, et al. Icarus, Triplicity and physical characteristics of Asteroid (216) KleopatraFeb. 2011.
    14. ↑ Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73, pp. 98–118, Bibcode:2012P&SS...73...98C, arXiv:1203.4336 Freely accessible, doi:10.1016/j.pss.2012.03.009. See Table 1.
    15. ↑ Scaltriti, F.; Zappala, V. (May 1978). "Photoelectric photometry of asteroids 37, 80, 97, 216, 270, 313, and 471". Icarus: 428–435. Bibcode:1978Icar...34..428S. doi:10.1016/0019-1035(78)90178-1. Retrieved 22 April 2017.
    16. ↑ Weidenschilling, S. J.; Chapman, C. R.; Davis, D. R.; Greenberg, R.; Levy, D. H.; Vail, S. (May 1987). "Photometric geodesy of main-belt asteroids. I - Lightcurves of 26 large, rapid rotators". Icarus: 191–245. Bibcode:1987Icar...70..191W. ISSN 0019-1035. doi:10.1016/0019-1035(87)90131-X. Retrieved 22 April 2017.
    17. ↑ Kennedy, H. D.; Tholen, D. J. (December 1981). "The brightness variations of asteroid 216 Kleopatra". Astronomical Society of Australia: 414–417. Bibcode:1982PASAu...4..414K. ISSN 0066-9997. Retrieved 22 April 2017.
    18. ↑ Pilcher, Frederick; Tholen, David J. (September 1982). "216 Kleopatra: Visual Lightcurves of a Large Amplitude Asteroid". The Minor Planet Bulletin. 9: 13–17. Bibcode:1982MPBu....9...13P. Retrieved 22 April 2017.
    19. ↑ Magnusson, P. (December 1982). "Determination of spin axis orientation for asteroids 44 Nysa, 216 Kleopatra and 624 Hektor". IN: Asteroids: 77–85. Bibcode:1983acm..proc...77M. Retrieved 22 April 2017.
    20. ↑ Zappala, V.; di Martino, M.; Scaltriti, F.; Djurasevic, G.; Knezevic, Z. (March 1983). "Photoelectric analysis of asteroid 216 Kleopatra Implications for its shape". Icarus: 458–464.ResearchsupportedbytheConsiglioNazionaledelleRicerche. Bibcode:1983Icar...53..458Z. ISSN 0019-1035. doi:10.1016/0019-1035(83)90210-5. Retrieved 22 April 2017.
    21. ↑ Magnusson, P. (October 1986). "Distribution of spin axes and senses of rotation for 20 large asteroids". Icarus: 1–39. Bibcode:1986Icar...68....1M. ISSN 0019-1035. doi:10.1016/0019-1035(86)90072-2. Retrieved 22 April 2017.
    22. ↑ Magnusson, P. (May 1990). "Spin vectors of 22 large asteroids". Icarus: 229–240. Bibcode:1990Icar...85..229M. ISSN 0019-1035. doi:10.1016/0019-1035(90)90113-N. Retrieved 22 April 2017.
    23. ↑ Drummond, J. D.; Weidenschilling, S. J.; Chapman, C. R.; Davis, D. R. (January 1991). "Photometric geodesy of main-belt asteroids. IV - an updated analysis of lightcurves for poles, periods, and shapes". Icarus: 44–64. Bibcode:1991Icar...89...44D. ISSN 0019-1035. doi:10.1016/0019-1035(91)90086-9. Retrieved 22 April 2017.
    24. ↑ Kaasalainen, M.; Viikinkoski, M. (July 2012). "Shape reconstruction of irregular bodies with multiple complementary data sources". Astronomy and Astrophysics. 543: 9. Bibcode:2012A&A...543A..97K. doi:10.1051/0004-6361/201219267. Retrieved 22 April 2017.
    25. ↑ Lupishko, D. F.; Velichko, F. P. (February 1987). "The sense of rotation of asteroids 21, 63, 216, and 349". Kinematika i Fizika Nebesnykh Tel: 57–65.InRussian. Bibcode:1987KFNT....3...57L. ISSN 0233-7665. Retrieved 22 April 2017.
    26. ↑ Drummond, J. D.; Weidenschilling, S. J.; Chapman, C. R.; Davis, D. R. (October 1988). "Photometric geodesy of main-belt asteroids. II - Analysis of lightcurves for poles, periods, and shapes". Icarus: 19–77. Bibcode:1988Icar...76...19D. ISSN 0019-1035. doi:10.1016/0019-1035(88)90139-X. Retrieved 22 April 2017.
    27. ↑ De Angelis, G. (May 1995). "Asteroid spin, pole and shape determinations". Planetary and Space Science. 43 (5): 649–682. Bibcode:1995P&SS...43..649D. doi:10.1016/0032-0633(94)00151-G. Retrieved 22 April 2017.
    28. ↑ Fauvaud, S.; Sareyan, J.-P.; Boussuge, J.; Bernhard, P. (September 2001). "Photometric Observations of the Minor Planet 216 Kleopatra". The Minor Planet Bulletin. 28: 44–45. Bibcode:2001MPBu...28...44F. Retrieved 22 April 2017.
    29. 1 2 3 4 5 Behrend, Raoul. "Asteroids and comets rotation curves – (216) Kleopatra". Geneva Observatory. Retrieved 22 April 2017.
    30. ↑ Warner, Brian D. (December 2006). "Asteroid lightcurve analysis at the Palmer Divide Observatory - March - June 2006". The Minor Planet Bulletin. 33 (4): 85–88. Bibcode:2006MPBu...33...85W. ISSN 1052-8091. Retrieved 22 April 2017.
    31. ↑ Alton, Kevin B. (April 2009). "CCD Lightcurve Analysis of 216 Kleopatra". The Minor Planet Bulletin. 36 (2): 69. Bibcode:2009MPBu...36...69A. ISSN 1052-8091. Retrieved 22 April 2017.
    32. ↑ Shevchenko, Vasilij G.; Velichko, Feodor P.; Checha, Vitaly A.; Krugly, Yurij N. (July 2014). "Photometric Study of Selected Asteroids". The Minor Planet Bulletin. 41 (3): 195–198. Bibcode:2014MPBu...41..195S. ISSN 1052-8091. Retrieved 22 April 2017.
    33. ↑ Belskaya, I. N.; Fornasier, S.; Tozzi, G. P.; Gil-Hutton, R.; Cellino, A.; Antonyuk, K.; et al. (March 2017). "Refining the asteroid taxonomy by polarimetric observations". Icarus. 284: 30–42. Bibcode:2017Icar..284...30B. doi:10.1016/j.icarus.2016.11.003. Retrieved 22 April 2017.
    34. ↑ Harris, A. W.; Young, J. W. (October 1989). "Asteroid lightcurve observations from 1979-1981". Icarus: 314–364. Bibcode:1989Icar...81..314H. ISSN 0019-1035. doi:10.1016/0019-1035(89)90056-0. Retrieved 22 April 2017.
    35. ↑ "Numbered Minor Planets 1–5000", Discovery Circumstances, IAU Minor Planet center, retrieved 2013-04-07
    36. ↑ Marchis, F; et al. (1999), (216) Kleopatra (7308), Central Bureau for Astronomical Telegrams, retrieved 2013-08-27
    37. ↑ Gradie, J.; Flynn, L. (March 1988), "A Search for Satellites and Dust Belts Around Asteroids: Negative Results", Abstracts of the Lunar and Planetary Science Conference, 19, pp. 405–406, Bibcode:1988LPI....19..405G.
    38. ↑ F. Marchis; SETI Institute, UC Berkeley; et al. (2008-09-18). "Composite image of (216) Kleopatra observed with the 10m-Keck II telescope". Space.com. Retrieved 2008-10-02.
    39. ↑ Franck Marchis (Principal Investigator, SETI Institute, UC Berkeley). "Two Companions Found Near Dog-Bone Asteroid". SETI Institute. Retrieved 2009-10-26.
    40. ↑ MPC 73983

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