1447 Utra

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1447 Utra
Discovery [1]
Discovered by Y. Väisälä
Discovery site Turku Obs.
Discovery date 26 January 1938
MPC designation (1447) Utra
Named after
Utra (Finnish town)[2]
1938 BB · 1936 SB
1951 KO · A918 FA
main-belt · (middle)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 98.67 yr (36,038 days)
Aphelion 2.6404 AU
Perihelion 2.4299 AU
2.5352 AU
Eccentricity 0.0415
4.04 yr (1,474 days)
0° 14m 39.12s / day
Inclination 4.7865°
Physical characteristics
Dimensions 11.83±0.86 km[4]
11.834±0.122 km[5]
12.634±0.103 km[6]
13.26±0.53 km[7]
13.58 km (calculated)[3]
257±30 h[a]
0.20 (assumed)[3]
11.30[4][6][7] · 11.60±0.44[8] · 11.7[1][3]

1447 Utra, provisional designation 1938 BB, is a stony asteroid, slow rotator and suspected tumbler from the central region of the asteroid belt, approximately 12 kilometers in diameter. It was discovered on 26 January 1938, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland.[9] The asteroid was named for the Finnish town of Utra.[2]

Orbit and classification[edit]

Utra is a S-type asteroid. It orbits the Sun in the central main-belt at a distance of 2.4–2.6 AU once every 4.04 years (1,474 days). Its orbit has an eccentricity of 0.04 and an inclination of 5° with respect to the ecliptic.[1] Utra was first identified as A918 FA at Heidelberg Observatory in 1918. The body's observation arc begins with its official discovery observation at Turku in 1938.[9]

Physical characteristics[edit]

Slow rotator[edit]

In March 2011, a rotational lightcurve of Utra was obtained from photometric observations by astronomer Luis E. Martinez. Lightcurve analysis gave a long rotation period of 257 hours with a brightness variation of 0.63 magnitude (U=2). This slow rotator is also a suspected tumbler (T0).[a]

Diameter and albedo[edit]

According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Utra measures between 11.83 and 13.26 kilometers in diameter, and its surface has an albedo between 0.303 and 0.381.[4][5][6][7] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 13.58 kilometers with an absolute magnitude of 11.7.[3]


This minor planet was named for Utra, a northeastern Finnish town and birthplace of the discoverer.[2] The approved naming citation was published by the Minor Planet Center before November 1977 (M.P.C. 2277).[10]


  1. ^ a b Martinez (2011) web: rotation period 257±30 hours with a brightness amplitude of 0.63 mag. Summary figures for (1447) Utra at Collaborative Asteroid Lightcurve Link (CALL). The referenced website was a non-recoverable dead link.


  1. ^ a b c d "JPL Small-Body Database Browser: 1447 Utra (1938 BB)" (2016-11-14 last obs.). Jet Propulsion Laboratory. Retrieved 25 July 2017. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1447) Utra. Springer Berlin Heidelberg. p. 116. ISBN 978-3-540-00238-3. Retrieved 4 January 2017. 
  3. ^ a b c d e f "LCDB Data for (1447) Utra". Asteroid Lightcurve Database (LCDB). Retrieved 4 January 2017. 
  4. ^ 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 4 January 2017. 
  5. ^ a b 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 4 January 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" (PDF). The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 4 January 2017. 
  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:1209.5794Freely accessible. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 4 January 2017. 
  8. ^ 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 4 January 2017. 
  9. ^ a b "1447 Utra (1938 BB)". Minor Planet Center. Retrieved 4 January 2017. 
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 4 January 2017. 

External links[edit]