Prediction and observation of a stellar occultation by Haumea's satellite Namaka

Abstract

Stellar occultations are an ideal way to characterize the physical and orbital properties of trans-Neptunian binary systems. In this research note, we detail the prediction and observation of a stellar occultation observed with NASA's IRTF on March 16${}^{\mathrm{th}}$, 2025 (UT), with drop-outs from both the dwarf planet Haumea and its smaller satellite Namaka. This occultation places a lower limit of 83 $\pm$ 2 km on Namaka's diameter. We also discuss the possibility that this detection could help to constrain the orbit of Namaka, measure Haumea's gravitational harmonics, and provide a path to measuring the internal structure of Haumea.

Accepted in Research Notes of the American Astronomical Society