Radiometric and Photometric Measurement of the Size and Shape of 2003 EL61

The Kuiper Belt is a modern frontier that holds clues to the early history of the Solar System as well as the ongoing interactions with nearby matter. The most unique and complex Kuiper Belt object is 2003 EL61, a rapidly-rotating, elongated body with 2 satellites and 7 dynamically-related family members. We use infrared radiometry and visible photometry to measure the size, shape and albedo of 2003 EL61. We have modified a standard thermal model(STM) to account for the highly non-spherical geometry of the object. By varying physical parameters of the object we compare Spitzer data to our modified STM. We also model the reflected light off an ellipsoidal object and compare it to photometry from Hubble. The HST data has resolved out the satellites and is the first visible photometry of just the object itself. The improved data as well as the modified thermal and reflected emission models will help us better constrain the size, shape, and albedo of 2003 EL61.