129990

129990 is a minor planet in the outer region of the asteroid belt, orbiting the Sun between Mars and Jupiter. It was discovered on October 12, 1999, by astronomers at the Lincoln Laboratory ETS in Socorro, New Mexico, as part of the Lincoln Near-Earth Asteroid Research (LINEAR) project. The asteroid is classified as a main-belt asteroid, with a semi-major axis of approximately 3.1 astronomical units (AU), a period of 5.5 years, and an orbital eccentricity of 0.14. Its absolute magnitude is 15.3, indicating a diameter of roughly 2.5 kilometers. The asteroid's spectral type is unknown, but it is likely a C-type asteroid, which are carbonaceous and typically found in the outer asteroid belt. 129990 has a rotation period of about 5.5 hours and an axial tilt of approximately 30 degrees. It is named after the discoverer's institution, the Lincoln Laboratory.