The Taiwanese-American Occultation Survey (TAOS)/Transneptunian Automated Occultation Survey (TAOS II)
The Taiwanese-American Occultation Survey (TAOS) began operations on Lulin Mountain in Chia-Yi in 2005. TAOS is a collaboration between ASIAA, National Central University (NCU), Harvard-Smithosonian Center for Astrophysics, and Yonsei University in South Korea. By monitoring some 1000 stars per night with 2048x2048 CCD cameras, this project searches for the occultation of background stars by Solar system bodies located in the Kuiper Belt. The utilization of 4 telescopes allows us to discriminate against false detections due to terrestrial events which do not produce coincident events over all telescopes.
Because objects in the outer Solar system only shine by reflected sunlight, they are undetectable if their sizes are small and if they are distant. Occultation of background stars is much less sensitive to size, and therefore can extend the detection of these objects to much greater distances in the Solar disk. Our 7-year result sets a very tight constraint on the population of objects larger than 700m in our solar system. This has important implications on how planets might have formed by the collisions of these objects.
From 2013, we have upgraded our camera, with a 1K x 1K frame transfer camera. With the new camera, we can reduce the background noise and enhance the sampling frequency of the observation to 10 Hz. This will enhance the detection efficiency of small KBOs.
Our detection rate is limited by the performance of the telescopes, and the relatively poor weather and atmospheric conditions at Lulin. We are therefore building the TAOS II system, with three new 1.3m diameter telescopes. We will place TAOS II at the San Pedro de Martir (SPM) site in Mexico, belonging to the Mexican National Astronomical Observatory (OAN), at an elevation of 2800m. With larger telescopes, fast cameras, and a better site in Mexico, TAOS II will push the observable limit of our Solar System by an order of magnitude from a distance of 100 to 1000 AU, allowing the delivery of better number densities for different sizes of these small bodies.