855 Newcombia (prov. designation: or ) is a stony background asteroid from the inner regions of the asteroid belt. It was discovered on 3 April 1916, by astronomer Sergey Belyavsky at the Simeiz Observatory on the Crimean peninsula. The S-type asteroid has a notably short rotation period of 3.0 hours and measures approximately in diameter. It was named after Canadian–American astronomer Simon Newcomb (1835–1909). Orbit and classification Newcombia is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. It orbits the Sun in the inner main-belt at a distance of 1.9–2.8 AU once every 3 years and 8 months (1,326 days; semi-major axis of 2.36 AU). Its orbit has an eccentricity of 0.18 and an inclination of 11° with respect to the ecliptic. Discovery Newcombia was discovered by Soviet-Russian astronomer Sergey Belyavsky at the Simeiz Observatory on the Crimean peninsula on 3 April 1916. The body's observation arc begins three weeks later, with its independent discovery by Max Wolf at Heidelberg Observatory on 28 April 2016. The Minor Planet Center, however, only credits the first discoverer. Naming This minor planet was named after Simon Newcomb (1835–1909), a Canadian–American professor of astronomy and director of the U.S. Nautical Almanac Office at the United States Naval Observatory. He worked on cometary and planetary orbits and is known for his Tables of the Motion of the Earth on its Axis and Around the Sun, a mathematical development of the position of the Earth in the Solar System. Newcomb also measured the speed of light and revised the astronomical unit. The was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (). The lunar crater Newcomb as well as the Martian crater Newcomb were also named in his honor. Physical characteristics In the SDSS-based taxonomy, Newcombia is a common, stony S-type asteroid. Rotation period In October 2004, a rotational lightcurve of Newcombia was obtained from photometric observations by American amateur astronomer Walter R. Cooney Jr. in collaboration with John Gross, Dirk Terrell, Vishnu Reddy and Ron Dyvig. Lightcurve analysis gave a well-defined rotation period of hours with a brightness variation of magnitude (). An identical period of hours with an amplitude of magnitude was determined in April 2014, by Daniel Klinglesmith and colleagues at the Etscorn Observatory in New Mexico (). Klinglesmith also published a period of in November