1187 Afra

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1187 Afra
001187-asteroid shape model (1187) Afra.png
Modelled shape of Afra from its lightcurve
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date6 December 1929
(1187) Afra
Named after
1929 XC
Orbital characteristics[3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc90.16 yr (32,932 d)
Aphelion3.2285 AU
Perihelion2.0523 AU
2.6404 AU
4.29 yr (1,567 d)
0° 13m 46.92s / day
Physical characteristics
Mean diameter
  • 31.83±3.9 km[6]
  • 31.96±0.33 km[7]
  • 32.348±0.299 km[8]
  • 14.06993±0.00001 h[9]
  • 14.0701±0.0005 h[10]
  • 14.09±0.02 h[11]
  • 14.645±0.006 h[12]
SMASS = X[3]

1187 Afra (prov. designation: 1929 XC) is a dark background asteroid from the central regions of the asteroid belt. It was discovered by German astronomer Karl Reinmuth at Heidelberg Observatory on 6 December 1929.[1] The X-type asteroid has a rotation period of 14.1 hours and measures approximately 32 kilometers (20 miles) in diameter. The origin of the asteroid's name remains unknown.

Orbit and classification[edit]

Afra is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.[4][5] It orbits the Sun in the central asteroid belt at a distance of 2.1–3.2 AU once every 4 years and 3 months (1,567 days; semi-major axis of 2.64 AU). Its orbit has an eccentricity of 0.22 and an inclination of 11° with respect to the ecliptic.[3] The body's observation arc begins at Heidelberg in January 1930, seven weeks after its official discovery observation.[1]


It is not known to what person, group of persons, or occurrence the name "Afra" refers to.[2]

Unknown meaning[edit]

Among the many thousands of named minor planets, Afra is one of 120 asteroids, for which no official naming citation has been published. All of these low-numbered asteroids have numbers between 164 Eva and 1514 Ricouxa and were discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth.[13]

Physical characteristics[edit]

The lightcurve of Afra shows a periodicity of 14.09±0.02 hours, during which time the brightness of the object varies by 0.40±0.02 in magnitude.[11][14]


  1. ^ a b c d e "1187 Afra (1929 XC)". Minor Planet Center. Retrieved 14 March 2020.
  2. ^ a b Schmadel, Lutz D. (2007). "(1187) Afra". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 100. doi:10.1007/978-3-540-29925-7_1188. ISBN 978-3-540-00238-3.
  3. ^ a b c d e "JPL Small-Body Database Browser: 1187 Afra (1929 XC)" (2020-02-04 last obs.). Jet Propulsion Laboratory. Archived from the original on 18 September 2020. Retrieved 14 March 2020.
  4. ^ a b "Asteroid 1187 Afra – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 14 March 2020.
  5. ^ a b "Asteroid 1187 Afra". Small Bodies Data Ferret. Retrieved 14 March 2020.
  6. ^ a b 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 14 March 2020.
  7. ^ a b 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. (online, AcuA catalog p. 153)
  8. ^ a b Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System. Bibcode:2016PDSS..247.....M. Retrieved 14 March 2020.
  9. ^ Ďurech, J.; Hanuš, J.; Oszkiewicz, D.; Vančo, R. (March 2016). "Asteroid models from the Lowell photometric database". Astronomy and Astrophysics. 587: A48. arXiv:1601.02909. Bibcode:2016A&A...587A..48D. doi:10.1051/0004-6361/201527573. ISSN 0004-6361.
  10. ^ Behrend, Raoul. "Asteroids and comets rotation curves – (1187) Afra". Geneva Observatory. Retrieved 14 March 2020.
  11. ^ a b Menke, John; Cooney, Walt; Gross, John; Terrell, Dirk; Higgins, David (October 2008). "Asteroid Lightcurve Analysis at Menke Observatory" (PDF). Minor Planet Bulletin. 35 (4): 155–160. Bibcode:2008MPBu...35..155M. ISSN 1052-8091.
  12. ^ Clark, Maurice (July 2019). "Asteroid Photometry from the Preston Gott Observatory" (PDF). Minor Planet Bulletin. 46 (3): 346–349. Bibcode:2019MPBu...46..346C. ISSN 1052-8091.
  13. ^ Schmadel, Lutz D. (2007). "Appendix 11 – Minor Planet Names with Unknown Meaning". Dictionary of Minor Planet Names – Fifth Revised and Enlarged revision. Springer Berlin Heidelberg. pp. 927–929. ISBN 978-3-540-00238-3.
  14. ^ "LCDB Data for (1187) Afra". Asteroid Lightcurve Database (LCDB). Retrieved 14 March 2020.

External links[edit]