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1550 Tito, provisional designation 1937 WD, is a stony asteroid from the middle region of the asteroid belt, approximately 12 kilometers in diameter. It was discovered on 29 November 1937, by Serbian astronomer Milorad B. Protić at the Belgrade Astronomical Observatory in Serbia.[15] It was named for Yugoslavian statesman Josip Broz Tito.[2]

1550 Tito
Discovery [1]
Discovered byM. B. Protitch
Discovery siteBelgrade Obs.
Discovery date29 November 1937
MPC designation(1550) Tito
Named after
Josip Broz Tito (statesman)[2]
1937 WD · 1941 XA
1941 YE · 1945 WB
1949 UR · 1983 CG3
main-belt · (middle)
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc79.34 yr (28,979 days)
Aphelion3.3418 AU
Perihelion1.7471 AU
2.5444 AU
4.06 yr (1,482 days)
0° 14m 34.08s / day
Physical characteristics
Dimensions9.47±2.13 km[3]
11.391±0.108 km[4]
11.45±0.28 km[5]
11.98±0.15 km[6]
12.39 km (calculated)[7]
12.431±0.062 km[8]
12.88±2.28 km[9]
13.652±2.335 km[10]
30±1 h[11]
54.2±0.3 h[12]
54.53±0.01 h[13]
0.20 (assumed)[7]
SMASS = S[1] · S[7]
11.8[5][6][8][9][10] · 11.9[1][7] · 11.96±0.39[14] · 12.12[3]

Classification and orbitEdit

This asteroid orbits the Sun at a distance of 1.7–3.3 AU once every 4 years and 1 month (1,482 days). Its orbit has an eccentricity of 0.31 and an inclination of 9° with respect to the ecliptic.[1] Tito's observation arc begins 4 years after its official discovery observation, with its first used observation taken at Belgrade in 1941. No precoveries were taken and no prior identifications were made.[15]

Physical characteristicsEdit

In the SMASS classification, Tito is characterized as a common S-type asteroid.[1]

Rotation periodEdit

Tito has a rotation period of approximately 54 hours. While this does not make it a slow rotator, it has a significantly longer period than the vast majority of minor planets, which typically spin every 2 to 20 hours around their axis. Rotational lightcurves of Tito were obtained from photometric observations by Walter R. Cooney Jr. in January 2003, who derived a period of 54.2 hours (Δmag 0.23, U=2),[12] by Raymond Poncy in December 2006, who obtained a shorter, provisional period of 30 hours (Δmag 0.16, U=2),[11] and by David Higgins in December 2010, who derived a period of 54.53 hours (Δmag 0.40, U=2).[13]

Diameter and albedoEdit

According to the surveys carried out by the Spitzer Space Telescope, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Tito measures between 9.47 and 13.652 kilometers in diameter, and its surface has an albedo between 0.181 and 0.257.[3][4][5][6][8][9][10] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 12.39 kilometers with an absolute magnitude of 11.9.[7]


Tito was named in honour of Josip Broz Tito (1892–1980), leader of the Yugoslavian resistance during the World War II, early enthusiast of the United Nations, and president of former Yugoslavia.[2] The official naming citation was published by the Minor Planet Center before November 1977 (M.P.C. 2277).[16]


  1. ^ a b c d e f "JPL Small-Body Database Browser: 1550 Tito (1937 WD)" (2017-05-05 last obs.). Jet Propulsion Laboratory. Retrieved 5 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1550) Tito". Dictionary of Minor Planet Names – (1550) Tito. Springer Berlin Heidelberg. p. 123. doi:10.1007/978-3-540-29925-7_1551. ISBN 978-3-540-00238-3.
  3. ^ 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 30 December 2016.
  4. ^ 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:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 30 December 2016.
  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:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 30 December 2016.
  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 30 December 2016.
  7. ^ a b c d e "LCDB Data for (1550) Tito". Asteroid Lightcurve Database (LCDB). Retrieved 30 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 c d 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. Retrieved 30 December 2016.
  10. ^ a b c d Ryan, E. L.; Mizuno, D. R.; Shenoy, S. S.; Woodward, C. E.; Carey, S. J.; Noriega-Crespo, A.; et al. (June 2015). "The kilometer-sized Main Belt asteroid population revealed by Spitzer". Astronomy and Astrophysics. 578: 12. arXiv:1204.1116. Bibcode:2015A&A...578A..42R. doi:10.1051/0004-6361/201321375. Retrieved 30 December 2016.
  11. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1550) Tito". Geneva Observatory. Retrieved 30 December 2016.
  12. ^ a b Cooney, Walter R., Jr.; Pozzoli, Valentino; Gross, John (March 2004). "Rotation period and lightcurve of minor planet 1550 Tito". The Minor Planet Bulletin. 31 (1): 23–24. Bibcode:2004MPBu...31...23C. ISSN 1052-8091. Retrieved 30 December 2016.
  13. ^ a b Higgins, David; Benishek, Validimir (April 2011). "Period Determination of Asteroid 1550 Tito". The Minor Planet Bulletin. 38 (2): 79–80. Bibcode:2011MPBu...38...79H. ISSN 1052-8091. Retrieved 30 December 2016.
  14. ^ 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 30 December 2016.
  15. ^ a b "1550 Tito (1937 WD)". Minor Planet Center. Retrieved 30 December 2016.
  16. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 30 December 2016.

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