21387

21387 is a minor planet in the outer region of the asteroid belt, orbiting the Sun between Mars and Jupiter. It was discovered on February 24, 1998, by the Lincoln Near-Earth Asteroid Research (LINEAR) team at the Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico. The asteroid is classified as a main-belt asteroid, with a semi-major axis of approximately 3.1 astronomical units (AU), an orbital period of about 5.6 Earth years, and an eccentricity of 0.11. Its absolute magnitude is 14.1, which corresponds to a diameter of roughly 4.5 kilometers, assuming an albedo of 0.15. The asteroid's rotation period is estimated to be around 5.7 hours. 21387 has a relatively low inclination of 1.8 degrees, indicating that its orbit is nearly circular and lies close to the ecliptic plane. The asteroid's spectral type is not well-determined, but it is likely to be a C-type, which suggests a composition rich in carbonaceous material. As of now, there are no known moons or significant physical features associated with 21387. The asteroid's designation and discovery information are maintained by the Minor Planet Center, which is responsible for the collection and dissemination of astrometric observations and orbits for minor planets.