A Single-chord Stellar Occultation by the Extreme Trans-Neptunian Object (541132) Lele\={a}k\={u}honua

TL;DR

This paper reports a stellar occultation observation of the trans-Neptunian object Leleākūhonua, providing new constraints on its size, albedo, and precise position, enhancing understanding of distant solar system objects.

Contribution

It presents the first occultation-based size and albedo estimates for Leleākūhonua, a large-perihelion trans-Neptunian object, using a single detection and a nondetection.

Findings

Radius estimated at 110 km with uncertainties

Geometric albedo approximately 0.21

High-precision astrometric data obtained

Abstract

A stellar occultation by the extreme large-perihelion trans-Neptunian object (541132) Lele\={a}k\={u}honua (also known by the provisional designation of 2015 TG387) 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 $r={110}_{-10}^{+14}$ km, corresponding to a geometric albedo ${p}_{V}={0.21}_{-0.05}^{+0.03}$, 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.