1393 Sofala, provisional designation 1936 KD, is a Vestian asteroid from the inner regions of the asteroid belt, approximately 11 kilometers in diameter. It was discovered on 25 May 1936, by South African astronomer Cyril Jackson at the Union Observatory in Johannesburg.[10] The asteroid was named after the province of Sofala in Mozambique.[2]
The asteroid was first identified as 1928 FBatHeidelberg Observatory in March 1928. The body's observation arc begins with its official discovery observation at Johannesburg in 1936.[10]
The asteroid has an ambiguous lightcurve. While a lightcurve, obtained at the Palomar Transient Factory in September 2013, gave a rotation period of 108.259 hours with a brightness amplitude of 0.48 magnitude (U=2),[8] another lightcurve modeled from combined dense and sparse photometry gave a sidereal period of 16.5931 hours.(U=2).[7] If the first result were correct, Sofala would be one of few hundred known slow rotators with a period above 100 hours. The Lightcurve Data Base, however, adopts the shorter period from the modeled lightcurve.[3] A third lightcurve with a period of 7.8 hours by René Roy from 2008 has received a poor rating.[6]
The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 11.30 kilometers based on an absolute magnitude of 12.1.[3]
^ abHanus, J.; Durech, J.; Broz, M.; Marciniak, A.; Warner, B. D.; Pilcher, F.; et al. (March 2013). "Asteroids' physical models from combined dense and sparse photometry and scaling of the YORP effect by the observed obliquity distribution". Astronomy and Astrophysics. 551: 16. arXiv:1301.6943. Bibcode:2013A&A...551A..67H. doi:10.1051/0004-6361/201220701.
^Schmadel, Lutz D. "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN978-3-642-01964-7.
