18687

18687 is a minor planet orbiting the Sun in the asteroid belt. It was discovered on February 16, 1977, by astronomers Eleanor Helin and Schelte Bus at the Palomar Observatory in California. The asteroid is named after the year of its discovery, 1977. It has an estimated diameter of about 5 kilometers and completes one orbit around the Sun approximately every 4.4 Earth years. The orbital path of 18687 is relatively stable, with a semi-major axis of about 2.7 astronomical units and an eccentricity of 0.1. The asteroid's rotation period is approximately 5.5 hours. 18687 is classified as a main-belt asteroid, a group of asteroids that orbit the Sun between Mars and Jupiter. It is not known to have any moons or to be part of any known asteroid family. The asteroid's spectral type is S, indicating that it has a stony composition. 18687 is not considered a potentially hazardous object, as its orbit does not bring it close to Earth.