Ogle-2017-Blg-1434lb: Confirmation Of A Cold Super-Earth Using Keck Adaptive Optics

The microlensing event OGLE-2017-BLG-1434 features a cold super-Earth planet that is 1 of 11 microlensing planets with a planet-host-star mass ratio of q < 1 x 10(-4). We provide an additional mass-distance constraint on the lens host using near-infrared adaptive optics photometry from Keck/NIRC2. We are able to determine a flux excess of K ( L ) = 16.96 +/- 0.11, which most likely comes entirely from the lens star. Combining this with constraints from the large Einstein ring radius, theta ( E ) = 1.40 +/- 0.09 mas, and OGLE parallax we confirm this event as a super-Earth with a mass of m ( p ) = 4.43 +/- 0.25M (circle plus). This system lies at a distance of D ( L ) = 0.86 +/- 0.05 kpc from Earth and the lens star has a mass of M ( L ) = 0.234 +/- 0.012M (circle dot). We confirm that with a star-planet mass ratio of q = 0.57 x 10(-4), OGLE-2017-BLG-1434 lies near the inflexion point of the planet-host mass-ratio power law.