1182 Ilona

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1182 Ilona
001182-asteroid shape model (1182) Ilona.png
Modelled shape of Ilona from its lightcurve
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date3 March 1927
(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 arc90.33 yr (32,993 days)
Aphelion2.5261 AU
Perihelion1.9930 AU
2.2596 AU
3.40 yr (1,241 days)
0° 17m 24.72s / day
Physical characteristics
Dimensions12.67±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]


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.[15]

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]


  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). "(1182) Ilona". Dictionary of Minor Planet Names – (1182) Ilona. Springer Berlin Heidelberg. p. 99. doi:10.1007/978-3-540-29925-7_1183. ISBN 978-3-540-00238-3.
  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:1509.02522. 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:1606.08923. 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". 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. 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. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 22 October 2019.
  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. (online, AcuA catalog p. 153)
  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:1504.04041. 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:1506.00762. 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 978-3-540-00238-3.

External links[edit]