A Single-chord Stellar Occultation by the Extreme Trans-Neptunian Object (541132) Leleākūhonua

A stellar occultation by the extreme large-perihelion trans-Neptunian object (541132) Leleākūhonua (also known by the provisional designation of 2015 TG 387 ) was predicted by the Lucky Star project and observed with the Research and Education Collaborative Occultation Network on 2018 October 20 UT. A single detection and a nearby nondetection provide constraints for the size and albedo. When a circular profile is assumed, the radius is km, corresponding to a geometric albedo , for an adopted absolute magnitude of H V = 5.6, typical of other objects in dynamically similar orbits. The occultation also provides a high-precision astrometric constraint.