5751 Zao

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Discovery and designation
Discovered by M. Koishikawa
Discovery site Ayashi Station
Discovery date January 5, 1992
MPC designation 5751
Named after
Mount Zaō
1992 AC
Minor planet category Amor Amor
Orbital characteristics[1]
Epoch May 14, 2008
Aphelion 2.993785803 ± 2.114e-08 AU
Perihelion 1.21607607 ± 1.6591e-07 AU
2.104930938 ± 1.4863e-08 AU
Eccentricity .422272697 ± 7.6573e-08
1115.463089 ± 1.1815e-05 d
115.323764 ± 2.5873e-05°
Inclination 16.0689199 ± 8.3868e-06°
121.723507 ± 1.6679e-05°
25.210457 ± 2.605e-05°
Physical characteristics
Dimensions 2.3 km[2]
76 hr[2]

5751 Zao also designated 1992 AC is an Amor asteroid discovered on January 5, 1992 by M. Koishikawa at the Ayashi Station of the Sendai Astronomical Observatory.

Physical properties[edit]

5751 Zao has been observed by several groups to determine its rotational period. Its light curve was observed by Pravec, et al. between 1992 and 1995 with the intention of determining its rotational period. From its nearly constant brightness it was determined that the asteroid is roughly spherical and has a rotational period of ≥ 21.7 hr.[3] Another group led by Wisniewski conducted an approximately 5 hour observation and were unable to conclude a rotational period.[4] 5751 Zao was again observed in 2001 by Delbó, et al. using the Keck telescope. They were able to determine the asteroid's albedo of 0.36 and re-classify the asteroid from X-type to E-type.[5] Using the asteroid's albedo and the Near Earth Asteroid Thermal Model (NEATM) the asteroid's diameter was estimated to be 2.3 km.[5] Further study of the asteroid by the Ondrejov Asteroid Photometry Project concludes that a rotational period of 76 hours is consistent with earlier measurements.[2][6]

External links[edit]


  1. ^ "JPL Small-Body Database Browser on 5751 Zao". NASA. 
  2. ^ a b c d "5751 Zao". European Asteroid Research Node. 
  3. ^ Pravec, P.; et al. (December 1997). "The Near-Earth Objects Follow-Up Program". Icarus 130 (2): 275–286. Bibcode:1997Icar..130..275P. doi:10.1006/icar.1997.5816. 
  4. ^ Wisniewski, W. Z.; MichaŁowski, T. M.; Harris, A. W.; McMillan, R. S. (April 1997). "Photometric Observations of 125 Asteroids". Icarus 126 (2): 395–449. Bibcode:1997Icar..126..395W. doi:10.1006/icar.1996.5665. 
  5. ^ a b Delbó, Marco; Harris, Alan W.; Binzel, Richard P.; Pravec, Petr; Davies, John K. (November 2003). "Keck observations of near-Earth asteroids in the thermal infrared". Icarus 166 (1): 116–130. Bibcode:2003Icar..166..116D. doi:10.1016/j.icarus.2003.07.002. 
  6. ^ "Ondrejov Asteroid Photometry Project: Summary of Prepublished Data".