2637 Bobrovnikoff, provisional designation A919 SB, is a background asteroid from the inner regions of the asteroid belt, approximately 6 kilometers (4 miles) in diameter. It was discovered on 22 September 1919, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in Heidelberg, Germany. The presumed spherical  S-type asteroid has a rotation period of 4.79 hours. It is named after astronomer  Nicholas Bobrovnikoff, who was the director of the Perkins Observatory in Ohio, United States.
Orbit and classification
Bobrovnikoff is a non- family asteroid from the main belt's background population. It orbits the Sun in the  inner asteroid belt at a distance of 1.7–2.8 AU once every 3 years and 5 months (1,237 days; semi-major axis of 2.26 AU). Its orbit has an eccentricity of 0.23 and an inclination of 5 ° with respect to the ecliptic. The body's  observation arc begins at Heidelberg in 1919, three days after its official discovery observation.
Bobrovnikoff is an assumed, stony S-type asteroid.
In September 2007, a rotational
lightcurve of Bobrovnikoff was obtained from photometric observations by French and Swiss astronomers Pierre Antonini, Raoul Behrend, and Alain Klotz. Lightcurve analysis gave a well-defined rotation period of 4.7939 hours with a brightness amplitude of 0.13 magnitude, indicative of a rather spherical shape ( ). U=3
Diameter and albedo
According to the survey carried out by the
NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Bobrovnikoff measures between 5.82 and 6.919 kilometers in diameter and its surface has an albedo between 0.2563 and 0.37.   
Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a larger diameter of 7.46 kilometers based on an absolute magnitude of 13.0.
minor planet was named after Russian-born cometary spectroscopist Nicholas Theodore Bobrovnikoff (1896–1988), known for his research on the 1910-apparition of Halley's Comet. From 1934 to 1951, he was the director of the Perkins Observatory in Delaware, Ohio. The naming was proposed by the director of Minor Planet Center, Brian G. Marsden, and the official citation was published on 24 July 1983 ( ). M.P.C. 8064 
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"Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0 . Retrieved . 6 April 2018
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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.
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Behrend, Raoul. "Asteroids and comets rotation curves – (2637) Bobrovnikoff". Geneva Observatory . Retrieved . 6 April 2018
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.
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