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161989 Cacus
Shape model of Cacus from its lightcurve
Discovery [1] [2]
Discovered by H.-E. Schuster
Discovery site La Silla Obs.
Discovery date8 February 1978
Designations
(161989) Cacus
Named after
 Cacus ( Roman mythology) [2]
1978 CA
Apollo · NEO · PHA [1]
Orbital characteristics [1]
Epoch 4 September 2017 ( JD 2458000.5)
Uncertainty parameter 0
Observation arc38.59 yr (14,096 days)
Aphelion1.3634 AU
Perihelion0.8828 AU
1.1231 AU
Eccentricity0.2140
1.19 yr (435 days)
345.40 °
0° 49m 41.16s / day
Inclination26.060°
161.24°
102.16°
Earth  MOID0.0152 AU · 5.9 LD
Physical characteristics
Mean diameter
0.64±0.02  km [3]
1.126±0.073 km [4]
1.86 km [5]
1.9 km [6]
3.7538±0.0019  h [6]
3.756 h [7]
3.761 h [5]
3.77±0.11 h [8]
0.09 [6]
0.119 (derived) [6]
0.199±0.052 [4]
0.46±0.09 [3]
Tholen = S [1] [6] · Q [9]
B–V = 0.910 [1]
U–B = 0.484 [1]
16.58 [6] [7] · 17.1 [4] · 17.2 [1] · 17.32 [5] · 17.43 [3]

161989 Cacus ( prov. designation: 1978 CA) is a stony asteroid, classified as near-Earth object and a potentially hazardous asteroid of the Apollo group, approximately 1 kilometer in diameter. It was discovered on 8 February 1978, by German astronomer Hans-Emil Schuster at ESO's La Silla Observatory in northern Chile. [2] Its orbit is confined between Venus and Mars.

This minor planet was named from Roman mythology, after Cacus, a fire-breathing monster, which was killed by Hercules. [2] The official naming citation was published by the Minor Planet Center on 24 November 2007 ( M.P.C. 61270). [10]

Close approaches [1]
Date JPL SBDB
nominal geocentric
distance 		uncertainty
region
( 3-sigma)
1941-09-02 2418754 km ± 6 km
2022-09-01 8607710 km ± 21 km [11]

References

  1. ^ a b c d e f g h "JPL Small-Body Database Browser: 161989 Cacus (1978 CA)" (2016-09-12 last obs.). Jet Propulsion Laboratory. Archived from the original on 22 November 2020. Retrieved 13 January 2018.
  2. ^ a b c d "161989 Cacus (1978 CA)". Minor Planet Center. Retrieved 13 January 2018.
  3. ^ a b c Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv: 1606.08923. Bibcode: 2016AJ....152...63N. doi: 10.3847/0004-6256/152/3/63.
  4. ^ a b c 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. arXiv: 1109.6407. Bibcode: 2011ApJ...741...90M. doi: 10.1088/0004-637X/741/2/90. S2CID  35447010.
  5. ^ a b c Degewij, J.; Lebofsky, L.; Lebofsky, M. (March 1978). "1978 CA and 1978 DA". IAU Circ. 3193 (3193): 1. Bibcode: 1978IAUC.3193....1D. Retrieved 13 January 2018.
  6. ^ a b c d e f "LCDB Data for (161989) Cacus". Asteroid Lightcurve Database (LCDB). Retrieved 13 January 2018.
  7. ^ a b Schuster, H. E.; Surdej, A.; Surdej, J. (September 1979). "Photoelectric observations of two unusual asteroids - 1978 CA and 1978 DA". Astronomy and Astrophysics Supplement Series. 37: 483–486. Bibcode: 1979A&AS...37..483S.
  8. ^ Koehn, Bruce W.; Bowell, Edward G.; Skiff, Brian A.; Sanborn, Jason J.; McLelland, Kyle P.; Pravec, Petr; et al. (October 2014). "Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) - 2009 January through 2009 June". The Minor Planet Bulletin. 41 (4): 286–300. Bibcode: 2014MPBu...41..286K. ISSN  1052-8091.
  9. ^ Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delbó, Marco; Hora, Joseph L.; Mueller, Michael (January 2014). "Physical characterization of Warm Spitzer-observed near-Earth objects". Icarus. 228: 217–246. arXiv: 1310.2000. Bibcode: 2014Icar..228..217T. doi: 10.1016/j.icarus.2013.10.004.
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 13 January 2018.
  11. ^ "Horizons Batch for 2022-Sep-01 06:54 UT". JPL Horizons. Archived from the original on 17 January 2022. Retrieved 17 January 2022.

External links

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