139815

139815 is a minor planet in the asteroid belt, located between the orbits of Mars and Jupiter. It was discovered on September 24, 1999, by the Lincoln Near-Earth Asteroid Research (LINEAR) project, a collaborative effort between the United States Air Force, NASA, and MIT. The asteroid is classified as a main-belt asteroid, with a semi-major axis of approximately 2.7 astronomical units (AU) and an orbital period of about 4.5 Earth years.

The size of 139815 is estimated to be around 3.5 kilometers in diameter, based on its absolute magnitude and assumed albedo. Its orbit is relatively stable, with an eccentricity of about 0.1 and an inclination of around 10 degrees relative to the ecliptic plane. The asteroid's spectral type is not well-determined, but it is likely to be a C-type asteroid, which are common in the outer asteroid belt and are characterized by their dark, carbonaceous surfaces.

139815 has not been visited by any spacecraft, and its physical properties, such as its shape, rotation period, and composition, remain unknown. However, ongoing observations and studies of its orbit and spectral characteristics can provide valuable insights into the formation and evolution of the asteroid belt. The asteroid's designation, 139815, is a unique identifier assigned by the Minor Planet Center, which is responsible for the collection and dissemination of data on minor planets and comets.