1684 Iguassú

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1684 Iguassú
Discovery [1]
Discovered byM. Itzigsohn
Discovery siteLa Plata Obs.
Discovery date23 August 1951
MPC designation(1684) Iguassú
Named after
Iguazu Falls (South America)[2]
1951 QE · 1934 LN
1935 SK1 · 1939 HK
1949 DE · 1950 JT
1965 AA1 · A922 DA
main-belt · (outer)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc94.75 yr (34,606 days)
Aphelion3.4852 AU
Perihelion2.7109 AU
3.0980 AU
5.45 yr (1,992 days)
0° 10m 50.52s / day
Physical characteristics
30.5±3.0 km[5]
30.62 km (calculated)[3]
31.381±0.336 km[6]
9.1423±0.0033 h[7]
9.230±0.170 h[8]
0.057 (assumed)[3]
10.700±0.140 (R)[8] · 10.8[6] · 10.848±0.001 (R)[7] · 10.90[5] · 10.91±0.21[9] · 11.0[1] · 11.3[3]

1684 Iguassú, provisional designation 1951 QE, is a carbonaceous asteroid from the outer region of the asteroid belt, approximately 30.5 kilometers in diameter. It was discovered on 23 August 1951, by Argentine astronomer Miguel Itzigsohn at the La Plata Astronomical Observatory, located in the city of La Plata, Argentina.[10] It was named after the Iguazu Falls in South America.[2]

Orbit and classification[edit]

The asteroid orbits the Sun in the outer main-belt at a distance of 2.7–3.5 AU once every 5 years and 5 months (1,992 days). Its orbit has an eccentricity of 0.13 and an inclination of 4° with respect to the ecliptic.[1]

Physical characteristics[edit]

Iguassú is characterized as a carbonaceous C-type asteroid.[3][9]

Rotation period[edit]

In January 2014, two rotational lightcurves of Iguassú were obtained at the Palomar Transient Factory in California. They gave a rotation period of 9.14 and 9.23 hours, respectively, both with a brightness change of 0.15 in magnitude (U=2/2).[7][8]

Diameter and albedo[edit]

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Iguassú measures between 30.21 and 31.38 kilometers in diameter, and its surface has an albedo between 0.08 and 0.093.[4][5][6] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 30.62 kilometers based on an absolute magnitude of 11.3.[3]


This minor planet is named for the large Iguazu Falls, a 60 meters high and 1 kilometer wide waterfall, which river of the same name marks part of the boundary between Argentina and Brazil.[2] As a curiosity, the spelling of the minor planet's name (Iguassú) neither concurs with the Spanish "Iguazú" nor with the Portuguese "Iguaçu". It is rather similar to "Yguasu", used in the native Guarani language, from which the waterfall's name originates. The official naming citation was published by the Minor Planet Center on 8 April 1982 (M.P.C. 6832).[11]


  1. ^ a b c d "JPL Small-Body Database Browser: 1684 Iguassu (1951 QE)" (2016-11-19 last obs.). Jet Propulsion Laboratory. Retrieved 6 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1684) Iguassú". Dictionary of Minor Planet Names – (1684) Iguassú. Springer Berlin Heidelberg. p. 134. doi:10.1007/978-3-540-29925-7_1685. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f g "LCDB Data for (1684) Iguassú". Asteroid Lightcurve Database (LCDB). Retrieved 22 December 2016.
  4. ^ 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 22 December 2016.
  5. ^ a b c d Alí-Lagoa, V.; Licandro, J.; Gil-Hutton, R.; Cañ; ada-Assandri, M.; Delbo', M.; et al. (June 2016). "Differences between the Pallas collisional family and similarly sized B-type asteroids". Astronomy and Astrophysics. 591: 11. Bibcode:2016A&A...591A..14A. doi:10.1051/0004-6361/201527660. Retrieved 22 December 2016.
  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 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 22 December 2016.
  8. ^ a b c Chang, Chan-Kao; Ip, Wing-Huen; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang; et al. (August 2015). "Asteroid Spin-rate Study Using the Intermediate Palomar Transient Factory". The Astrophysical Journal Supplement Series. 219 (2): 19. arXiv:1506.08493. Bibcode:2015ApJS..219...27C. doi:10.1088/0067-0049/219/2/27. Retrieved 22 December 2016.
  9. ^ a b c 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 22 December 2016.
  10. ^ "1684 Iguassu (1951 QE)". Minor Planet Center. Retrieved 22 December 2016.
  11. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 22 December 2016.

External links[edit]