2156 Kate, provisional designation A917 SH, is a stony, rare-type asteroid from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. The asteroid was discovered on 23 September 1917, by Soviet–Russian astronomer Sergey Belyavsky at Simeiz Observatory on the Crimean peninsula. It was named for Kate Kristensen, wife of astronomer L. K. Kristensen.
Kate orbits the Sun in the inner main-belt at a distance of 1.8–2.7 AU once every 3 years and 4 months (1,226 days). Its orbit has an eccentricity of 0.20 and an inclination of 5° with respect to the ecliptic. As no precoveries were taken, and no prior identifications were made, the asteroid's observation arc begins with its official discovery observation at Simeiz in 1917.
According to the survey carried out by the NEOWISE mission of NASA's space-based Wide-field Infrared Survey Explorer, Kate measures 8.131 kilometers in diameter and its surface has an albedo of 0.189 and 0.2242, respectively, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 8.61 kilometers with an absolute magnitude of 12.69.
This minor planet was named after Kate Kristensen, wife of astronomer L. K. Kristensen, who was involved in the body's orbit computation. The official naming citation was published by the Minor Planet Center on 1 April 1980 (M.P.C. 5284).