1496 Turku

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1496 Turku
Discovery [1]
Discovered by Y. Väisälä
Discovery site Turku Obs.
Discovery date 22 September 1938
MPC designation (1496) Turku
Named after
Turku[2] (Finnish city)
1938 SA1 · 1928 QN
1928 RE · 1950 EC
1954 MH · 1957 HB
main-belt · (inner)
Flora[3] · background [4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 88.02 yr (32,148 days)
Aphelion 2.5631 AU
Perihelion 1.8490 AU
2.2060 AU
Eccentricity 0.1619
3.28 yr (1,197 days)
0° 18m 2.88s / day
Inclination 2.5005°
Physical characteristics
Dimensions 7.47±0.31 km[5]
7.758±0.072 km[6]
7.973±0.018 km[7]
8.19 km (calculated)[3]
6.47±0.01 h[8]
6.47375±0.00001 h[9]
0.24 (assumed)[3]
S (assumed)[3]
12.40[5] · 12.42±0.25[10] · 12.6[1][3] · 12.9[7]

1496 Turku, provisional designation 1938 SA1, is a Florian asteroid from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 22 September 1938, by astronomer Yrjö Väisälä at the Iso-Heikkilä Observatory in Turku, Finnland,[11] the asteroid was named for the Finnish city of Turku.[2]

Orbit and classification[edit]

Turku is a member of the Flora family (402), a giant asteroid family and the largest family of stony asteroids in the main belt.[3] It is, however, a non-family asteroid from the main belt's background population when applying the Hierarchical Clustering Method to its proper orbital elements.[4]

It orbits the Sun in the inner main-belt at a distance of 1.8–2.6 AU once every 3 years and 3 months (1,197 days). Its orbit has an eccentricity of 0.16 and an inclination of 3° with respect to the ecliptic.[1] The body's observation arc begins with its first identification as 1928 QN at Johannesburg Observatory in August 1928, more than 10 years prior to its official discovery observation at Turku.[11]

Physical characteristics[edit]

Turku is an assumed S-type asteroid, which is also the Flora family's overall spectral type.[3]

Rotation period and poles[edit]

In April 2006, a rotational lightcurve of Turku was obtained from photometric observations by French amateur astronomer Laurent Bernasconi. Lightcurve analysis gave a rotation period of 6.47 hours with a brightness amplitude of 0.51 magnitude, indicative of a non-spherical shape (U=3-).[8]

A 2016-published lightcurve, using modeled photometric data from the Lowell Photometric Database, gave a concurring period of 6.47375 hours, as well as a spin axis of (75.0°, −75.0°) in ecliptic coordinates (λ, β).[9]

Diameter and albedo[edit]

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Turku measures between 7.47 and 7.973 kilometers in diameter and its surface has an albedo between 0.1930 and 0.347.[5][6][7]

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the largest member and namesake of the Flora family – and calculates a diameter of 8.19 kilometers based on an absolute magnitude of 12.6.[3]


This minor planet was named after Finnish city of Turku, location of the discovering observatory and home of the discoverer Yrjö Väisälä; in ancient times, Turku was the capital of Finland.[2] The official naming citation was published by the Minor Planet Center before November 1977 (M.P.C. 1350).[12]


  1. ^ a b c d "JPL Small-Body Database Browser: 1496 Turku (1938 SA1)" (2016-08-23 last obs.). Jet Propulsion Laboratory. Retrieved 27 September 2017. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1496) Turku. Springer Berlin Heidelberg. p. 119. ISBN 978-3-540-00238-3. Retrieved 27 September 2017. 
  3. ^ a b c d e f g h "LCDB Data for (1496) Turku". Asteroid Lightcurve Database (LCDB). Retrieved 27 September 2017. 
  4. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 27 September 2017. 
  5. ^ 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 27 September 2017. 
  6. ^ 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:1406.6645Freely accessible. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 27 September 2017. 
  7. ^ 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 27 September 2017. 
  8. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1496) Turku". Geneva Observatory. Retrieved 27 September 2017. 
  9. ^ a b Durech, J.; Hanus, J.; Oszkiewicz, D.; Vanco, R. (March 2016). "Asteroid models from the Lowell photometric database" (PDF). Astronomy and Astrophysics. 587: 6. arXiv:1601.02909Freely accessible. Bibcode:2016A&A...587A..48D. doi:10.1051/0004-6361/201527573. Retrieved 27 September 2017. 
  10. ^ 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 27 September 2017. 
  11. ^ a b "1496 Turku (1938 SA1)". Minor Planet Center. Retrieved 27 September 2017. 
  12. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 27 September 2017. 

External links[edit]