2197 Shanghai

2197 Shanghai, provisional designation, is a carbonaceous Themistian asteroid from the outer region of the asteroid belt, approximately 22 kilometers in diameter.

The asteroid was discovered on 30 December 1965, by astronomers at the Purple Mountain Observatory in Nanking, China, and named after the city of Shanghai.

Orbit and classification
Shanghai is a member of the Themis family, a dynamical family of outer-belt asteroids with nearly coplanar ecliptical orbits. It orbits the Sun at a distance of 2.8–3.6 AU once every 5 years and 7 months (2,047 days). Its orbit has an eccentricity of 0.13 and an inclination of 2° with respect to the ecliptic.

Physical characteristics
The dark body has been characterized as a C-type asteroid.

Rotation period
In December 2010, a rotational lightcurve of Shanghai was obtained for this asteroid from photometric observations taken at the U.S. Palomar Transient Factory in California. It gave a rotation period of $20.198$ hours with a brightness variation of 0.16 magnitude (U=2).

One month later in January 2011, a similar period of $20.2$ hours with an amplitude of 0.16 magnitude was derived by French amateur astronomer Pierre Antonini (U=2).

Diameter and albedo
According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Shanghai measures 20.2 and 23.9 kilometers in diameter and its surface has an albedo of 0.119 and 0.106, respectively. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0898 and a diameter of 22.2 kilometers with an absolute magnitude of 11.5.

Naming
This minor planet is named after Shanghai, the most populous city of China (pop. 24 million as of 2014). Located in the Yangtze River Delta in eastern China, it has the world's busiest container port. The official naming citation was published by the Minor Planet Center on 1 June 1981 (M.P.C. 6059).