COLD CLASSICAL KBO 2014 MU69: READY FOR ITS CLOSE-UP

On January 1^st 2019 UT, the New Horizons spacecraft will conduct a close flyby of Kuiper Belt object 2014 MU₆₉ (MU69 henceforth), providing our first close view of a small body in heliocentric orbit in the Kuiper Belt. MU69 was discovered in June 2014 in a dedicated search for New Horizons flyby targets by the Hubble Space Telescope. Its low-inclination, near-circular orbit, with a semi-major axis of 44.2 AU, is very typical for a member of the Cold Classical Kuiper Belt, the least-disturbed, most primordial, population of small bodies in the solar system. The observed brightness of MU69 implies a diameter of 21 – 40 km, depending on the assumed albedo, but little else is yet known about its physical properties. Detailed planning of the New Horizons flyby will be accomplished over the next two years. However, preliminary plans include a close approach distance of 3,000 km, enabling images of MU69 with ~25 m/pixel resolution, 3x better than the best Pluto images, 500 m/pixel color imaging, and near-infrared compositional mapping with ~1km/pixel resolution. Additional observations will include visible-wavelength searches for possible satellites, rings, and comet-like dust coma, and UV and plasma searches for outgassing, along with measurements of day and night thermal emission at 4 cm wavelength. The result will be a comprehensive portrait of an entirely new class of solar system body, providing an important new window on the origin and evolution of the solar system.