dc.description.abstract | We have studied the stellar occultation probability calculation and searching for unknown variable stars in the Taiwanese-American Occultation Survey (TAOS) data. Our work is divided into two parts : (1) Stellar occultation probability calculation: Stellar occultation provides currently the only mean to detect small Kuiper-belt objects (KBOs). The number of detection of such events depends on the actual occurrence rate and the detectability. The event rate is determined by the distributed population of the KBOs, the surface number density of background stars, their angular sizes, and the relative shadow speed. The detectability of any event is related to the instruments and circumstances, such as the detector integration time, sampling rate, moon phase, sky variations, diffraction effect, etc. Here we report the computation of the probability of stellar occultation by KBOs from a geometric consideration. With a density of 1000 stars and 103.5 to 105.5 KBOs deg-2, and a relative shadow speed of 0.001” s-1, one expects about 10-8 stellar occultation events by KBOs to take place per hour of bservation. (2) Searching for unknown variable stars: The TAOS project has collected more than a billion photometric measurements since 2005 January. These sky survey data — covering timescales from a few hundred milliseconds to a few hundred days — are a powerful source to study stellar variability. There are 167 star fields monitored by TAOS. Here we summarize the first results of a search for periodic variable stars on one particular filed No. 151 (RA=17h30m7s, Dec=+27d17’30”), which has been observed at 47 epochs. In about a 3 deg square field, between 8 and 16 magnitude, we identified 89 candidate variables, among which only 7 are previously known. We present the analysis methodology for variability and show the light curves for the newly found variables, including 3 Cepheid, 3 RR Lyrae c type, 2 RR Lyrae ab type, 4 eclipsing binaries, and 5 long-period variables. | en_US |