139817

139817 is a minor planet in the outer region of the asteroid belt, approximately 12 kilometers in diameter. It was discovered on 22 September 2001, by astronomers of the Lincoln Near-Earth Asteroid Research at the Lincoln Laboratory's ETS near Socorro, New Mexico. The Minor Planet Center has credited the discovery under the provisional designation 2001 SW171. The asteroid is part of the Flora family, a large group of asteroids that share similar orbital elements and spectral characteristics.

The Flora family is named after 8 Flora, the largest member of the group, and is believed to have formed from the breakup of a larger parent body. Asteroids in this family are primarily composed of silicate minerals, with a surface that is relatively bright and featureless. The Flora family is located in the inner region of the asteroid belt, between the orbits of Mars and Jupiter.

139817 has an orbital period of approximately 1.75 Earth years and an orbital eccentricity of 0.12. Its orbit is inclined at an angle of about 1.6 degrees to the ecliptic plane. The asteroid's absolute magnitude is 13.3, which indicates its brightness and size. The rotational period of 139817 is not yet determined, but it is expected to be relatively short, similar to other asteroids in the Flora family.

The study of minor planets like 139817 contributes to our understanding of the formation and evolution of the solar system. By analyzing their orbits, compositions, and physical properties, astronomers can gain insights into the processes that shaped the asteroid belt and the planets that orbit within it.