1182 Ilona

1182 Ilona

Modelled shape of Ilona from its lightcurve
Discovery[1]
Discovered by	K. Reinmuth
Discovery site	Heidelberg Obs.
Discovery date	3 March 1927
Designations
MPC designation	(1182) Ilona
Named after	unknown[2]
Alternative designations	1927 EA · A915 RD
Minor planet category	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
Semi-major axis	2.2596 AU
Eccentricity	0.1180
Orbital period (sidereal)	3.40 yr (1,241 days)
Mean anomaly	328.01°
Mean motion	0° 17^m 24.72^s / day
Inclination	9.3881°
Longitude of ascending node	336.38°
Argument of perihelion	63.035°
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] 14.162±0.257[7] 14.26±0.8 km[8] 17.88±0.62 km[9]
Synodic rotation period	14.938±0.005 h[10] 29.8±0.1 h[11] 29.853±0.0627 h[12]
Geometric albedo	0.175±0.014[9] 0.2039 (derived)[3] 0.22±0.11[5] 0.221±0.016[7] 0.2624±0.030[8] 0.29±0.13[4] 0.2957±0.0367[6]
Spectral type	S[3]
Absolute magnitude (H)	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

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]

Naming

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

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

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

Rotation period and shape

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

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]

References

1. "JPL Small-Body Database Browser: 1182 Ilona (1927 EA)" (2017-07-02 last obs.). Jet Propulsion Laboratory. Retrieved 17 August 2017.
2. 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. "LCDB Data for (1182) Ilona". Asteroid Lightcurve Database (LCDB). Retrieved 17 August 2017.
4. 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. S2CID 9341381. Retrieved 17 August 2017.
5. 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.
6. 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. S2CID 35447010.
7. 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. S2CID 46350317. Retrieved 17 August 2017.
8. 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. 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. Behrend, Raoul. "Asteroids and comets rotation curves – (1182) Ilona". Geneva Observatory. Retrieved 17 August 2017.
11. 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. 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. S2CID 8342929. 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. S2CID 53493339. Retrieved 17 August 2017.
14. "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

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 1182 Ilona at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 1182 Ilona at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters