Non-spherical KBO shape identification in the TAOS-2 project

We explore the possibility of determining a non-spherical shape for Kuiper Belt Objects (KBOs) by analyzing diffraction effects in the context of the TAOS-2 occultation survey. We show how discrepancies between simulated diffraction patterns for spherical and irregular shapes, are related to the occulting KBO structure. Our results indicate that the possibility to constrain the KBO's shape is strongly related to the detectability of the diffraction pattern Poisson spot in the data. The consequence of this result is the restraint of size and distance for a KBO in order to detect a non-spherical shape. Since TAOS-2 will operate with three telescopes observing the same field simultaneously, the impact factor also plays an important role in shape detectability, since for non-spherical KBO occultations each telescope will have slightly different diffraction lightcurve. TAOS-2 will deliver a nominal photometry at 20 Hz, however in some cases it might be increased up to 40 Hz depending on the detector region and star brightness. This opens the possibility of improving the likelihood of measuring the Poisson spot, even in cases of maximum KBO relative motion, which diminishes the sampling resolution. In this context we propose the observation parameters that may lead to a better identification of the KBO occulting structure, in particular for the TAOS-2 survey.