Author Date


Degree Name



Physics and Astronomy


Physical and Mathematical Sciences

Defense Date


Publication Date


First Faculty Advisor

Darin Ragozzine

First Faculty Reader

Mike Joner

Honors Coordinator

Karine Chesnel


astronomy, photometry, Haumea, Hi'iaka, Trans-Neptunian Objects, Kuiper Belt Objects


The dwarf planet Haumea orbits near the edge of the Solar System in the Kuiper Belt. As it rotates, different parts of the object can be seen from Earth, so observing Haumea as it rotates allows us to see whether the surface is uniform or varied. Previous work has shown that one part of Haumea has a reddish dark spot, as opposed to the bright gray surface, and that Haumea has two nearby moons, the larger of which is called Hi’iaka. To better understand Haumea’s surface and Hi’iaka, we gathered new observations using BYU time at the Astronomical Research Consortium 3.5-m telescope at Apache Point Observatory. These data include ultraviolet measurements of the Haumea system in order to determine relative colors for Haumea (including its dark red spot) and its largest moon Hi’iaka. We fit sinusoidal models to this Haumea system data, including the unresolved contribution of Hi’iaka, using Bayesian parameter inference powered by Markov Chain Monte Carlo methods. We here present our model fits for the rotational light variation of Haumea and Hi’iaka, with implications for Haumea’s surface and formation. We also discuss the results of the model fits in terms of the relative colors iii of Haumea and Hi’iaka. This new information may lead to a better understanding of the origins and interactions of Haumea and Hi’iaka.