1182 Ilona

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1182 Ilona
Discovery [1]
Discovered by K. Reinmuth
Discovery site Heidelberg Obs.
Discovery date 3 March 1927
MPC designation (1182) Ilona
Named after
1927 EA · A915 RD
main-belt · (inner)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 90.33 yr (32,993 days)
Aphelion 2.5261 AU
Perihelion 1.9930 AU
2.2596 AU
Eccentricity 0.1180
3.40 yr (1,241 days)
0° 17m 24.72s / day
Inclination 9.3881°
Physical characteristics
Dimensions 12.67±2.95 km[4]
13.29±2.48 km[5]
13.448±0.074 km[6]
14.09 km (derived)[3]
14.26±0.8 km[8]
17.88±0.62 km[9]
14.938±0.005 h[10]
29.8±0.1 h[11]
29.853±0.0627 h[12]
0.2039 (derived)[3]
11.04±0.96[13] · 11.3[6][8][9] · 11.50[4][7] · 11.536±0.004 (R)[12] · 11.6[1][3] · 11.77[5]

1182 Ilona, provisional designation 1927 EA, is a stony asteroid from the inner regions of the asteroid belt, approximately 14 kilometers in diameter. It was discovered by German astronomer Karl Reinmuth at the Heidelberg Observatory on 3 March 1927, and later named Ilona. Any reference to its name is unknown.[14][2]

Classification and orbit[edit]

Ilona orbits the Sun in the inner main-belt at a distance of 2.0–2.5 AU once every 3 years and 5 months (1,241 days). Its orbit has an eccentricity of 0.12 and an inclination of 9° with respect to the ecliptic.[1] The asteroid was first identified as A915 RD at Bergedorf Observatory in September 1915. The body's observation arc, however, begins at Heidelberg one night after its official discovery observation.[14]

Physical characteristics[edit]

Ilona is an assumed stony S-type asteroid.[3]

Rotation period and shape[edit]

Three rotational lightcurve of Ilona were obtained from photometric observations. Lightcurve analysis gave a rotation period of 29.8 hours (including an alternative period solution 14.938 hours, or half the period) with a brightness variation of 0.98 to 1.20 magnitude (U=2/2/2).[10][11][12] A high brightness amplitude typically indicates that the body has a non-spheroidal shape.

Diameter and albedo[edit]

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, Ilona measures between 12.67 and 17.88 kilometers in diameter and its surface has an albedo between 0.175 and 0.2957.[4][5][6][7][8][9] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.2039 and calculates a diameter of 14.09 kilometers based on an absolute magnitude of 11.6.[3]


Any reference to a person or occurrence of this minor planet's name is unknown. The name was suggested by German astronomer Gustav Stracke.[2]

Unknown meaning[edit]

Among the many thousands of named minor planets, Ilona is one of 120 asteroids, for which no official naming citation has been published. All of these low-numbered asteroids have numbers between 164 Eva and 1514 Ricouxa and were discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth (also see category).[15]


  1. ^ a b c d "JPL Small-Body Database Browser: 1182 Ilona (1927 EA)" (2017-07-02 last obs.). Jet Propulsion Laboratory. Retrieved 17 August 2017. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1182) Ilona. Springer Berlin Heidelberg. p. 99. ISBN 978-3-540-00238-3. Retrieved 17 August 2017. 
  3. ^ a b c d e f g "LCDB Data for (1182) Ilona". Asteroid Lightcurve Database (LCDB). Retrieved 17 August 2017. 
  4. ^ a b c d Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522Freely accessible. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. Retrieved 17 August 2017. 
  5. ^ a b c d 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:1606.08923Freely accessible. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 17 August 2017. 
  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" (PDF). The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 17 August 2017. 
  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:1209.5794Freely accessible. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 17 August 2017. 
  8. ^ 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 17 August 2017. 
  9. ^ 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 17 August 2017. 
  10. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1182) Ilona". Geneva Observatory. Retrieved 17 August 2017. 
  11. ^ a b Lecrone, Crystal; Addleman, Don; Butler, Thomas; Hudson, Erin; Mulvihill, Alex; Reichert, Chris; et al. (September 2005). "2004-2005 winter observing campaign at Rose-Hulman Institute: results for 1098 Hakone, 1182 Ilona, 1294 Antwerpia, 1450 Raimonda, 2251 Tikhov, and 2365 Interkosmos". The Minor Planet Bulletin. 32 (3): 46–48. Bibcode:2005MPBu...32...46L. ISSN 1052-8091. Retrieved 17 August 2017. 
  12. ^ a b c Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041Freely accessible. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 17 August 2017. 
  13. ^ 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:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 17 August 2017. 
  14. ^ a b "1182 Ilona (1927 EA)". Minor Planet Center. Retrieved 17 August 2017. 
  15. ^ Schmadel, Lutz D. (2007). "Appendix 11 – Minor Planet Names with Unknown Meaning". Dictionary of Minor Planet Names – Fifth Revised and Enlarged revision. Springer Berlin Heidelberg. pp. 927–929. ISBN 3-540-00238-3. 

External links[edit]