21775

21775 is a minor planet in the asteroid belt, located between the orbits of Mars and Jupiter. It was discovered on October 24, 1999, by the Lowell Observatory Near-Earth-Object Search (LONEOS) at Anderson Mesa Station. The asteroid is classified as a main-belt asteroid, with a semi-major axis of approximately 2.7 astronomical units (AU). Its orbital period is roughly 4.5 Earth years, and it has an eccentricity of about 0.15, indicating a relatively circular orbit.

The size of 21775 is estimated to be around 4 kilometers in diameter, based on its absolute magnitude of 14.5. Its spectral type is not well-determined, but it is likely an S-type asteroid, which are composed mainly of silicate materials. The rotation period of 21775 is not known, but it is expected to be similar to other asteroids of its size.

The asteroid is named after the American astronomer and educator Clyde Tombaugh, who discovered Pluto in 1930. The naming citation was published by the Minor Planet Center on March 2, 2001 (M.P.C. 41678). As of now, there are no known moons or significant physical features associated with 21775.