4222 Nancita

4222 Nancita (prov. designation: ) is a bright background asteroid and upcoming Mars-crosser on an eccentric orbit from the inner regions of the asteroid belt. It was discovered on 13 March 1988, by American astronomer Eleanor Helin at Palomar Observatory in California, United States. The S-type asteroid has a rotation period of 3.9 hours and measures approximately 9 km in diameter. It was named after the discoverer's daughter-in-law, Nancy Coker Helin.

Orbit and classification
Nancita is a non-family asteroid from the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. It will become a Mars-crossing asteroid in June 2019. It orbits the Sun in the inner main-belt at a distance of 1.7–3.1 AU once every 3 years and 8 months (1,331 days). Its orbit has an eccentricity of 0.29 and an inclination of 4° with respect to the ecliptic. The asteroid was first observed as at McDonald Observatory in 1950. Its observation arc begins at Crimea–Nauchnij in 1968, when it observed as, or 20 years prior to its official discovery observation at Palomar.

Naming
This minor planet was named in honor of Nancy Coker Helin, daughter-in-law of the discoverer, and wife to Bruce Helin, after whom the minor planet 2430 Bruce Helin had previously been named. Nancy is described by the discoverer as a talented singer, composer and teacher, who has brought music and joy to her family. The was published by the Minor Planet Center on 2 December 1990 (M.P.C. 17466).

Physical characteristics
In the SMASS classification, Nancita is a common S-type asteroid.

Rotation and shape
A rotational lightcurve of Nancita, obtained from photometric observations at the Australian Hunters Hill Observatory and collaborating stations in 2006, gave a well-defined rotation period of 3.8732 hours with a high brightness amplitude of 0.97 in magnitude (U=3), indicating that the body has a non-spheroidal shape.

Diameter and albedo
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Nancita measures between 8.5 and 9.7 kilometers in diameter and its surface has an albedo in the range of 0.21 to 0.27. The Collaborative Asteroid Lightcurve Link agrees with the results obtained by IRAS.