1123 Shapleya

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1123 Shapleya
Discovery [1]
Discovered by G. Neujmin
Discovery site Simeiz Obs.
Discovery date 21 September 1928
MPC designation (1123) Shapleya
Named after
Harlow Shapley
(American astronomer)[2]
1928 ST · 1974 QQ2
2016 FJ6
main-belt · Flora[3]
Orbital characteristics[1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc 87.81 yr (32,073 days)
Aphelion 2.5741 AU
Perihelion 1.8758 AU
2.2250 AU
Eccentricity 0.1569
3.32 yr (1,212 days)
0° 17m 49.2s / day
Inclination 6.4212°
Physical characteristics
Dimensions 10.93±2.29 km[4]
11.282±0.136 km[5]
12.003±0.092 km[6]
12.08 km (taken)[3]
12.084 km[7]
12.32±0.84 km[8]
20 h (dated)[9]
24 h (dated)[10]
52.92±0.01 h[11]
11.55±0.29[12] · 11.59±0.13[3][7][9] · 11.60[4] · 11.7[1][6][8]

1123 Shapleya, provisional designation 1928 ST, is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 11 kilometers in diameter. It was discovered on 21 September 1928, by Russian astronomer Grigory Neujmin at Simeiz Observatory on the Crimean peninsula.[13] It was named after American astronomer Harlow Shapley.[2]

Orbit and classification[edit]

Shapleya is a S-type asteroid and member of the Flora family of stony asteroids, one of the largest families of the main belt. It orbits the Sun at a distance of 1.9–2.6 AU once every 3 years and 4 months (1,212 days). Its orbit has an eccentricity of 0.16 and an inclination of 6° with respect to the ecliptic.[1] As no precoveries were taken, and no prior identifications were made, the body's observation arc begins with its official discovery observation at Simeiz.[13]


In November 2011, the so-far best rated rotational lightcurve of was obtained by American astronomer Robert Stephens at the Center for Solar System Studies in California. Lightcurve analysis gave a rotation period of 52.92 hours with a brightness variation of 0.38 magnitude (U=3-),[11] superseding observations by Wiesław Z. Wiśniewski and a group of French, Italian and Swiss astronomers, that gave a shorter period of 20 and 24 hours, respectively (U=2/2).[9][10] Shapleya has a relatively slow rotation period, as most minor planets have a spin rate between 2 and 20 hours.

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, Shapleya measures between 10.93 and 12.32 kilometers in diameter, and its surface has an albedo between 0.26 and 0.36.[4][5][6][8] The Collaborative Asteroid Lightcurve Link adopts Petr Pravec's revised WISE data, that is, an albedo of 0.2797 and a diameter of 12.084 kilometers with an absolute magnitude of 11.59.[3][7]


This minor planet was named by the discoverer after Harlow Shapley (1885–1972), American astronomer and director of Harvard Observatory in Cambridge, Massachusetts.[2] The lunar crater Shapley and the Shapley Supercluster are also named after him. Naming citation was first mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 105).[2]


  1. ^ a b c d "JPL Small-Body Database Browser: 1123 Shapleya (1928 ST)" (2016-07-14 last obs.). Jet Propulsion Laboratory. Retrieved 14 March 2017.
  2. ^ a b c d Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1123) Shapleya. Springer Berlin Heidelberg. p. 95. ISBN 978-3-540-00238-3. Retrieved 14 March 2017.
  3. ^ a b c d e "LCDB Data for (1123) Shapleya". Asteroid Lightcurve Database (LCDB). Retrieved 14 March 2017.
  4. ^ 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 14 March 2017.
  5. ^ 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 14 March 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:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 14 March 2017.
  7. ^ a b c d Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026. Retrieved 14 March 2017.
  8. ^ 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 14 March 2017.
  9. ^ a b c Wisniewski, W. Z.; Michalowski, T. M.; Harris, A. W.; McMillan, R. S. (March 1995). "Photoelectric Observations of 125 Asteroids". Abstracts of the Lunar and Planetary Science Conference. Bibcode:1995LPI....26.1511W. Retrieved 14 March 2017.
  10. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1123) Shapleya". Geneva Observatory. Retrieved 14 March 2017.
  11. ^ a b Stephens, Robert D. (April 2012). "Asteroids Observed from GMARS and Santana Observatories: 2011 October- December". The Minor Planet Bulletin. 39 (2): 80–82. Bibcode:2012MPBu...39...80S. ISSN 1052-8091. Retrieved 14 March 2017.
  12. ^ 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 14 March 2017.
  13. ^ a b "1123 Shapleya (1928 ST)". Minor Planet Center. Retrieved 14 March 2017.

External links[edit]