952 Caia

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952 Caia
Discovery [1]
Discovered by G. Neujmin
Discovery site Simeiz Observatory
Discovery date 27 October 1916
MPC designation 952 Caia
Named after
Henryk Sienkiewicz
1916 Σ61 · 1973 WH
A908 EB · A919 GB
A921 RA
main-belt · (outer)[3]
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 99.14 yr (36,211 days)      
Aphelion 3.7257 AU
Perihelion 2.2520 AU
2.9889 AU
Eccentricity 0.2465
5.17 yr (1,887 days)
Inclination 10.034°
Physical characteristics
Dimensions 81.61±4.6 km (IRAS:12)[4]
87.97±0.97 km[5]
88.758±1.405 km[6]
85.02±0.91 km[7]
81.53 km (derived)[3]
7.51 h[8]
7.50±0.01 h[9]
3.795±0.001 h[10]
3.79 h[10]
0.0554±0.007 (IRAS:12)[4]
0.0506 (derived)[3]

952 Caia, provisional designation 1916 Σ61, is a large carbonaceous asteroid from the outer region of the asteroid belt, about 82 kilometers in diameter. It was discovered by Soviet–Russian astronomer Grigory Neujmin at the Crimean Simeiz Observatory on 27 October 1916.[11]

The C-type asteroid orbits the Sun at a distance of 2.3–3.7 AU once every 5 years and 2 months (1,887 days). Its orbit shows an eccentricity of 0.25 and an inclination of 10 degrees from the plane of the ecliptic.[1]

Two photoelectric light-curve observations from 1980 rendered a rotation period of 7.50 and 7.51 hours,[8][9] while a more recent light-curve analysis in 2004 gave a period of 3.795±0.001 hours (or half the previously determined period) with a very low brightness variation of 0.03 in magnitude, which typically indicates a nearly spheroidal shape.[10] 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, the asteroid has a diameter between 81.6 and 88.8 kilometers and a low albedo in the range of 0.040 and 0.056.[4][5][6][7] The Collaborative Asteroid Lightcurve Link agrees with the spaced-based observations and derives an albedo of 0.051 with a corresponding diameter of 81.5 kilometers.[3]

The body's odd provisional designation "1916 Σ61" was assigned at the discovering Simeiz Observatory during the First World War, when communication with the German Astronomisches Rechen-Institut, then in charge of assigning designations, was not possible over long periods of time. Instead, the observatory assigned their own, custom provisional designations containing the Greek letter sigma (Σ), in order to avoid multiple assignments. For simplicity, the letter sigma is often represented by the letter "S" (1916 S61).[1]

The minor planet was named after a heroine in the historical novel Quo Vadis written by Polish journalist, novelist and laureate of the Nobel Prize in Literature in 1905, Henryk Sienkiewicz (1846–1916).[2]


  1. ^ a b c d e "JPL Small-Body Database Browser: 952 Caia (1916 S61)" (2015-12-18 last obs.). Jet Propulsion Laboratory. Retrieved January 2016. 
  2. ^ a b Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (952) Caia. Springer Berlin Heidelberg. p. 84. ISBN 978-3-540-00238-3. Retrieved January 2016. 
  3. ^ a b c d e "LCDB Data for (952) Caia". Asteroid Lightcurve Database (LCDB). Retrieved January 2016. 
  4. ^ a b c d 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 January 2016. 
  5. ^ a b c d 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". Publications of the Astronomical Society of Japan 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved January 2016. 
  6. ^ a b c d 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. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved January 2016. 
  7. ^ a b c d 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. doi:10.1088/2041-8205/759/1/L8. Retrieved January 2016. 
  8. ^ a b Stanzel, R.; Schober, H. J. (January 1980). "The asteroids 118 Peitho and 952 CAIA - Rotation periods and lightcurves from photoelectric observations". Astronomy and Astrophysics Supplement Series: 3–5.ResearchsupportedbytheOesterreichischerFondszurFoerderungderwissenschaftlichenForschung. Bibcode:1980A&AS...39....3S. Retrieved January 2016. 
  9. ^ a b Harris, A. W.; Young, J. W. (July 1980). "Asteroid rotation. III - 1978 observations". Icarus: 20–32. Bibcode:1980Icar...43...20H. doi:10.1016/0019-1035(80)90084-6. Retrieved January 2016. 
  10. ^ a b c Behrend, Raoul. "Asteroids and comets rotation curves – (952) Caia". Geneva Observatory. Retrieved January 2016. 
  11. ^ "952 Caia (1916 S61)". Minor Planet Center. Retrieved January 2016. 

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