4606 Saheki

4606 Saheki, provisional designation 1987 UM₁, is a stony Flora asteroid from the inner regions of the asteroid belt, about 7 kilometers in diameter. It was discovered by Japanese astronomer Tsutomu Seki at Geisei Observatory, Japan, on 27 October 1987.

The S-type asteroid is a member of the Flora family, one of the largest groups of stony asteroids in the main-belt. It orbits the Sun at a distance of 2.0–2.5 AU once every 3 years and 5 months (1,234 days). Its orbit has an eccentricity of 0.10 and an inclination of 3° with respect to the ecliptic. The first precovery was taken at Palomar Observatory in 1953, extending the asteroid's observation arc by 34 years prior to its discovery.

In January 2009, a photometric light-curve analysis by David Higgins at Hunters Hill Observatory, Australia, rendered a well-defined rotation period of 7000496900000000000♠4.969±0.003 hours with a brightness variation of 0.56 in magnitude (U=3). Two months later, in March 2009, a second light-curve was obtained at the Via Capote Observatory, California, gave a period of 7000503200000000000♠5.032±0.001 and an amplitude of 0.68 in magnitude (U=3-). According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid has a high albedo of 0.33 and a diameter of 6.7 kilometers, while the Collaborative Asteroid Lightcurve Link (CALL) calculates a diameter of 7.1 kilometers, based on an assumed albedo of 0.24, which is identical to the albedo of the Flora family's namesake, the asteroid 8 Flora.

The minor planet was named after Japanese astronomer and president of the Toa Astronomical Society, Tsuneo Saheki (1916–1996). Over half a century, he as gathered large inventory of observational data of the planet Mars. The Martian crater Saheki is also named in his honour. Naming citation was published on 28 May 1991 (M.P.C. 18308).