203860

203860 is a numbered minor planet in the asteroid belt, provisionally designated 2002 MH4. It was discovered on June 9, 2002, by the Lincoln Near-Earth Asteroid Research (LINEAR) survey at the Socorro observing site in New Mexico, United States. The discovery occurred using a 1.0‑meter aperture telescope equipped with a CCD array that allows precise tracking of faint moving objects. The asteroid was subsequently assigned the permanent number 203860 by the Minor Planet Center following confirmation of its orbital elements.

Orbital parameters place 203860 in the central main belt. Its semi-major axis is approximately 2.4 astronomical units, which places it between the 3:1 mean‑motion resonance with Jupiter and the inner edge of the main belt. The asteroid has an orbital period of about 3.7 years and an eccentricity of roughly 0.12, giving it a slightly elongated trajectory. The inclination relative to the ecliptic is 8.6 degrees, indicating a modest tilt. Its orbit has an aphelion of about 2.66 AU and perihelion of about 2.14 AU, keeping it well within the main‑belt zone and not classifying it as a near‑Earth object.

The physical characteristics of 203860 are inferred mainly from photometric observations. Its absolute magnitude is listed as 15.5, suggesting a diameter in the range of 4–6 kilometers, assuming typical albedo values for S‑type asteroids. No spectroscopic or polarimetric data are available to precisely determine its taxonomic class; however, its orbital placement suggests a likely S‑type composition common to inner main‑belt bodies. Further observations, especially light‑curve studies, are needed to refine its rotation period, shape, and surface properties.

All available data for 203860 are regularly updated in the JPL Small‑Body Database and the Minor Planet Center’s official catalog, providing astronomers with a reliable reference for ongoing studies of main‑belt asteroids.