2156 Kate, provisional designation A917 SH, is a stony asteroid from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 23 September 1917, by Soviet–Russian astronomer Sergey Belyavsky at Simeiz Observatory on the Crimean peninsula.[24]

The S-type asteroid is also classified as a rather rare and uncommon A-type by Pan-STARRS' large-scale survey.[23] It orbits the Sun at a distance of 1.8–2.7 AU once every 3 years and 4 months (1,227 days). Its orbit has an eccentricity of 0.20 and an inclination of 5° with respect to the ecliptic.[3] As no precoveries were taken, the asteroid's observation arc begins with its discovery in 1917.[24]

A large number of rotational light-curves were obtained from photometric observations. They gave a well-defined rotation period of 5.620 to 5.623 hours with a brightness variation between 0.5 and 0.9 in magnitude (U=3/3-).[2][12][16][19]

According to the survey carried out by the NEOWISE mission of NASA's space-based Wide-field Infrared Survey Explorer, the asteroid measures 8.1 kilometers in diameter and its surface has an albedo of 0.22,[8] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 8.6 kilometers.

The minor planet was named after Kate Kristensen, wife of astronomer L. K. Kristensen, who was involved in the body's orbit computation.[4] Naming citation was published on 1 April 1980 (M.P.C. 5284).[25]