1106 Cydonia (/sɪˈdniə/), provisional designation 1929 CW, is a Eunomian asteroid from the central regions of the asteroid belt, approximately 13 kilometers (8 miles) in diameter. It was discovered on 5 February 1929, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in Germany.[11] The asteroid was named for the fruit-bearing tree Cydonia (quince).[2] The S-type asteroid has a relatively short rotation period of 2.7 hours.[3]

1106 Cydonia
Discovery [1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date5 February 1929
MPC designation(1106) Cydonia
Named after
Cydonia (quince) [2]
(flowering plant)
1929 CW
main-belt · (middle)
Orbital characteristics[1]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc88.41 yr (32,292 days)
Aphelion2.9246 AU
Perihelion2.2673 AU
2.5959 AU
4.18 yr (1,528 days)
0° 14m 8.16s / day
Physical characteristics
Mean diameter
12.140±0.093 km[5]
12.818±0.182 km[6]
12.95±0.94 km[7]
13.26 km (calculated)[3]
2.6700±0.0181 h[8]
2.679±0.001 h[9]
0.21 (assumed)[3]
SMASS = S[1][3]
11.60[7] · 11.7[3] · 11.8[1] · 12.0[6] · 12.06±0.28[10]

Orbit and classificationEdit

Cydonia is a member of the Eunomia family (502),[3][4] a prominent family of stony asteroids and the largest one in the intermediate main belt with more than 5,000 members.[12] It orbits the Sun in the central asteroid belt at a distance of 2.3–2.9 AU once every 4 years and 2 months (1,528 days; semi-major axis 2.60 AU). Its orbit has an eccentricity of 0.13 and an inclination of 13° with respect to the ecliptic.[1] The body's observation arc begins with its first and official discovery observation at Heidelberg in February 1929.[11]

Physical characteristicsEdit

In the SMASS classification, Cydonia is a stony S-type asteroid,[1][3] in-line with the Eunomia family's overall spectral type.[12]:23

Rotation periodEdit

In December 2015, a rotational lightcurve of Cydonia was obtained from photometric observations by astronomers at the Etscorn Observatory (719) in New Mexico, United States. Lightcurve analysis gave a well-defined rotation period of 2.679 hours with a brightness variation of 0.28 magnitude (U=3).[9] In April 2017, Spanish astronomers at Puçol Observatory (J42) and other stations of the APTOG-network measured a similar period of 2.6700 hours and an amplitude of 0.10 magnitude (U=2+).[8]

Diameter and albedoEdit

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Cydonia measures between 12.140 and 12.95 kilometers in diameter and its surface has an albedo between 0.1719 and 0.241.[5][6][7]

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.21 – derived from 15 Eunomia, the family's parent body and namesake – and calculates a diameter of 13.26 kilometers based on an absolute magnitude of 11.7.[3]


This minor planet was named after the genus Cydonia in the family Rosaceae, with the fruit-bearing quince tree as its only member. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 104).[2]

Reinmuth's flowersEdit

Due to his many discoveries, Karl Reinmuth submitted a large list of 66 newly named asteroids in the early 1930s. The list covered his discoveries with numbers between (1009) and (1200). This list also contained a sequence of 28 asteroids, starting with 1054 Forsytia, that were all named after plants, in particular flowering plants (also see list of minor planets named after animals and plants).[13]


  1. ^ a b c d e f "JPL Small-Body Database Browser: 1106 Cydonia (1929 CW)" (2017-07-05 last obs.). Jet Propulsion Laboratory. Retrieved 28 February 2018.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1106) Cydonia". Dictionary of Minor Planet Names – (1106) Cydonia. Springer Berlin Heidelberg. p. 94. doi:10.1007/978-3-540-29925-7_1107. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f g h i "LCDB Data for (1106) Cydonia". Asteroid Lightcurve Database (LCDB). Retrieved 28 February 2018.
  4. ^ a b "Asteroid 1106 Cydonia – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 26 October 2019.
  5. ^ a b 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.
  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. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
  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. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8.
  8. ^ a b Aznar Macias, Amadeo (July 2017). "Density and Axis-size Relationship of Five Main-belt Asteroids: 2017 January - March". The Minor Planet Bulletin. 44 (3): 276–279. Bibcode:2017MPBu...44..276A. ISSN 1052-8091. Retrieved 28 February 2018.
  9. ^ a b Klinglesmith, Daniel A., III; Hendrickx, Sebastian; Madden, Karl; Montgomery, Samuel (July 2016). "Asteroid Lightcurves from Estcorn Observatory". The Minor Planet Bulletin. 43 (3): 234–239. Bibcode:2016MPBu...43..234K. ISSN 1052-8091. Retrieved 28 February 2018.
  10. ^ 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.
  11. ^ a b "1106 Cydonia (1929 CW)". Minor Planet Center. Retrieved 28 February 2018.
  12. ^ a b Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). Identification and Dynamical Properties of Asteroid Families. Asteroids IV. pp. 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131.
  13. ^ Schmadel, Lutz D. (2007). "(1054) Forsytia". Dictionary of Minor Planet Names – (1054) Forsytia. Springer Berlin Heidelberg. p. 90. doi:10.1007/978-3-540-29925-7_1055. ISBN 978-3-540-00238-3.

External linksEdit