Status of the taos project and a simulator for tno occultation

The majority of trans-Neptunian objects (TNOs) are probably small comets beyond the orbit of Neptune. A study of TNOs may enable a better understanding of the origin of short-period comets and of the process of planet formation and the early history of the solar system. An occultation survey is currently the only way to detect these objects down to a size of a few kilometers at such a distance. The status of the Taiwan-America Occultation Survey (TAOS) project is reported. In order to monitor thousands of stars on the order of a fraction of a second using CCD cameras, a novel CCD readout technique, the '‘shutterless zipper mode,'’ is applied. Two predicted asteroid occultation events were successfully observed. Instead of a simple number count of occultation events, an interpretation of a TNO occultation survey result can be obtained by using the simulator described here. Through comparison of the results from an observation and from our simulator, a specific astronomical or astrophysical model can be constrained.