1524 Joensuu

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1524 Joensuu
Discovery [1]
Discovered byY. Väisälä
Discovery siteTurku Obs.
Discovery date18 September 1939
MPC designation(1524) Joensuu
Named after
Joensuu (Finnish town)[2]
1939 SB · 1931 EL
1933 QO · 1936 DG
1958 DH1
main-belt · (outer)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc85.95 yr (31,395 days)
Aphelion3.4881 AU
Perihelion2.7300 AU
3.1090 AU
5.48 yr (2,002 days)
0° 10m 47.28s / day
Physical characteristics
Dimensions39.37±12.22 km[4]
42.79±1.1 km[5]
42.83 km (derived)[3]
44.87±0.78 km[6]
45.056±0.291 km[7]
49.394±0.502 km[8]
9.276±0.007 h[9]
0.0505 (derived)[3]
10.56±0.50[11] · 10.60[7] · 10.7[1][3] · 10.78[4] · 10.8[5][6][8]

1524 Joensuu, provisional designation 1939 SB, is a carbonaceous asteroid from the outer region of the asteroid belt, approximately 42 kilometers in diameter. It was discovered on 18 September 1939, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland, and named for the town of Joensuu.[12]

Classification and orbit[edit]

Joensuu is a dark C-type asteroid, that orbits the Sun in the outer main-belt at a distance of 2.7–3.5 AU once every 5 years and 6 months (2,002 days). Its orbit has an eccentricity of 0.12 and an inclination of 13° with respect to the ecliptic.[1] In 1931, Joensuu was first identified as 1931 EL at Heidelberg Observatory, extending the body's observation arc by 8 years prior to its official discovery observation.[12]

Physical characteristics[edit]

In October 2005, a rotational lightcurve of Joensuu was obtained from photometric observations by French amateur astronomer Laurent Bernasconi. It gave a well-defined rotation period of 9.276 hours with a change in brightness of 0.33 magnitude (U=3).[9]

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, Joensuu measures between 39.37 and 49.39 kilometers in diameter, and its surface has an albedo between 0.034 and 0.07.[4][5][6][7][8] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0505 and a diameter of 42.83 kilometers using an absolute magnitude of 10.7.[3]


This minor planet was named for the Finnish town Joensuu, where the discoverer received his early schooling. It is located in North Karelia, near the Russian border.[2] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3929).[13]


  1. ^ a b c d "JPL Small-Body Database Browser: 1524 Joensuu (1939 SB)" (2017-02-26 last obs.). Jet Propulsion Laboratory. Retrieved 30 June 2017.
  2. ^ a b Schmadel, Lutz D. (2007). "(1524) Joensuu". Dictionary of Minor Planet Names – (1524) Joensuu. Springer Berlin Heidelberg. p. 121. doi:10.1007/978-3-540-29925-7_1525. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f "LCDB Data for (1524) Joensuu". Asteroid Lightcurve Database (LCDB). Retrieved 31 December 2016.
  4. ^ 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 31 December 2016.
  5. ^ 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.
  6. ^ 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 October 2019. (online, AcuA catalog p. 153)
  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 31 December 2016.
  8. ^ 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.
  9. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1524) Joensuu". Geneva Observatory. Retrieved 31 December 2016.
  10. ^ 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 16 December 2016.
  11. ^ 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 31 December 2016.
  12. ^ a b "1524 Joensuu (1939 SB)". Minor Planet Center. Retrieved 31 December 2016.
  13. ^ Schmadel, Lutz D. "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.

External links[edit]