1479 Inkeri

1479 Inkeri, provisional designation, is an asteroid from the central regions of the asteroid belt. It is an exceptionally slow rotator, suspected tumbler and measures approximately 19 kilometers in diameter. It was discovered on 16 February 1938, by Finnish astronomer Yrjö Väisälä at the Iso-Heikkilä Observatory in Turku, Finland. "Inkeri" is the name of two of the discoverer's younger relatives as well as the local name of the former Finnish province of Ingria.

Orbit and classification
Inkeri is a non-family asteroid from the main belt's background population. It orbits the Sun in the central asteroid belt at a distance of 2.2–3.2 AU once every 4 years and 5 months (1,601 days). Its orbit has an eccentricity of 0.19 and an inclination of 7° with respect to the ecliptic.

The asteroid was first identified as at Simeiz Observatory in January 1916. The body's observation arc begins with its identification as at Heidelberg Observatory in September 1923, more than 14 years prior to its official discovery observation at Turku.

Physical characteristics
In the Tholen classification, Inkeri's spectral type is ambiguous (XFU). It is closest to that of an X-type asteroid and somewhat similar to the F-types. In addition, the spectrum has also been flagged as "unusual" (U).

Slow rotator and tumbler
In December 2011, a rotational lightcurve of Inkeri was obtained from photometric observations by Andrea Ferrero at the Bigmuskie Observatory, Italy, in collaboration with Frederick Pilcher at the Organ Mesa Observatory in New Mexico, United States. Analysis of the bimodal lightcurve gave an exceptionally long rotation period of 660 hours with a brightness amplitude of 1.30 magnitude (U=2+).

This makes it one of the slowest rotators known to exist. The observers also suspect that the body is a tumbling asteroid in a non-principal axis rotation. These results supersede previous period solutions of 5 and 12.55 hours (U=1/1).

Diameter and albedo
According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Inkeri measures between 15.206 and 31.86 kilometers in diameter and its surface has an albedo between 0.033 and 0.2222.

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.10 and calculates a diameter of 18.35 kilometers based on an absolute magnitude of 11.8.

Naming
This minor planet was named "Inkeri", a Finnish female name, held by Vaisala's granddaughter and niece. It is also the Finnish name of Ingria, a formerly-Finnish province near Saint Petersburg that is now part of Russia. The official was published by the Minor Planet Center in January 1956 (M.P.C. 1350).