952 Caia

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952 Caia
Discovery [1]
Discovered byG. Neujmin
Discovery siteSimeiz Obs.
Discovery date27 October 1916
MPC designation(952) Caia
Named after
1916 Σ61 · 1973 WH
A908 EB · A919 GB
A921 RA
main-belt · (outer)[3]
Orbital characteristics[1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc99.63 yr (36,389 days)
Aphelion3.7294 AU
Perihelion2.2611 AU
2.9952 AU
5.18 yr (1,893 days)
0° 11m 24.36s / day
Physical characteristics
Dimensions81.53 km (derived)[3]
81.61±4.6 km (IRAS:12)[4]
85.02±0.91 km[5]
87.97±0.97 km[6]
88.758±1.405 km[8]
3.79 h[9]
3.795±0.001 h[9]
7.50±0.01 h[10]
7.51 h[11]
0.0506 (derived)[3]
0.0554±0.007 (IRAS:12)[4]
P[8] · C[3]
9.17±0.21[12] · 9.2[4][6][8] · 9.30[1][3][5]

952 Caia, provisional designation 1916 Σ61, is a carbonaceous background asteroid from the outer region of the asteroid belt, approximately 82 kilometers (51 miles) in diameter. It was discovered by Soviet–Russian astronomer Grigory Neujmin at the Crimean Simeiz Observatory on 27 October 1916.[13] It was named after the heroine in the novel Quo Vadis by Henryk Sienkiewicz.[2]

Orbit and classification[edit]

Caia is a non-family asteroid from the main belt's background population. It orbits the Sun in the outer asteroid belt at a distance of 2.3–3.7 AU once every 5 years and 2 months (1,893 days). Its orbit has an eccentricity of 0.25 and an inclination of 10° with respect to the ecliptic.[1] The first unused observation was made at the U.S Taunton Observatory (803) in 1908, when it was identified as 1908 EB, extending the body's observation arc by 8 years prior to its official discovery observation.[13]

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".[1]


This minor planet was named after "Caia", 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]

Physical characteristics[edit]

Caia is a carbonaceous C-type asteroid. It is also classified as a P-type asteroid by NASA's Wide-field Infrared Survey Explorer (WISE).[8]

Rotation period[edit]

Two photoelectric lightcurve observations from 1980 rendered a rotation period of 7.50 and 7.51 hours (U=2/2),[10][11] 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 (U=2), which typically indicates a nearly spheroidal shape.[9]

Diameter and albedo[edit]

According to the surveys carried out by the Infrared Astronomical Satellite, IRAS, the Japanese Akari satellite, and the WISE telescope 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][8] 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]


  1. ^ a b c d e "JPL Small-Body Database Browser: 952 Caia (1916 S61)" (2016-06-13 last obs.). Jet Propulsion Laboratory. Retrieved 12 December 2016.
  2. ^ a b c Schmadel, Lutz D. (2007). "(952) Caia". Dictionary of Minor Planet Names – (952) Caia. Springer Berlin Heidelberg. p. 84. doi:10.1007/978-3-540-29925-7_953. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f "LCDB Data for (952) Caia". Asteroid Lightcurve Database (LCDB). Retrieved 4 July 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: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 4 July 2016.
  5. ^ 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. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 4 July 2016.
  6. ^ 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 4 July 2016.
  7. ^ a b c Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 12 December 2016.
  8. ^ a b c d e f 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.
  9. ^ a b c Behrend, Raoul. "Asteroids and comets rotation curves – (952) Caia". Geneva Observatory. Retrieved 4 July 2016.
  10. ^ a b Harris, A. W.; Young, J. W. (July 1980). "Asteroid rotation. III - 1978 observations". Icarus. 43 (1): 20–32. Bibcode:1980Icar...43...20H. doi:10.1016/0019-1035(80)90084-6. Retrieved 4 July 2016.
  11. ^ 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. 39: 3–5.ResearchsupportedbytheOesterreichischerFondszurFoerderungderwissenschaftlichenForschung. Bibcode:1980A&AS...39....3S. Retrieved 4 July 2016.
  12. ^ 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. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 4 July 2016.
  13. ^ a b "952 Caia (1916 S61)". Minor Planet Center. Retrieved 4 July 2016.

External links[edit]