The Taiwanese-American Occultation Survey (TAOS) aims to detect serendipitous occultations of stars by small (~1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare (<10 ...super(-3) events per star per year) and short in duration (~200 ms), so many stars must be monitored at a high readout cadence. TAOS monitors typically ~500 stars simultaneously at a 5 Hz readout cadence with four telescopes located at Lulin Observatory in central Taiwan. In this paper, we report the results of the search for small Kuiper Belt objects (KBOs) in seven years of data. No occultation events were found, resulting in a 95% c.l. upper limit on the slope of the faint end of the KBO size distribution of q - 3.34-3.82, depending on the surface density at the break in the size distribution at a diameter of about 90 km.
We have analyzed the first 3.75 years of data from the Taiwanese American Occultation Survey (TAOS). TAOS monitors bright stars to search for occultations by Kuiper Belt objects (KBOs). This data set ...comprises 5 X 105 star hours of multi-telescope photometric data taken at 4 or 5 Hz. No events consistent with KBO occultations were found in this data set. We compute the number of events expected for the Kuiper Belt formation and evolution models of Pan & Sari, Kenyon & Bromley, Benavidez & Campo Bagatin, and Fraser. A comparison with the upper limits we derive from our data constrains the parameter space of these models. This is the first detailed comparison of models of the KBO size distribution with data from an occultation survey. Our results suggest that the KBO population is composed of objects with low internal strength and that planetary migration played a role in the shaping of the size distribution.
The Taiwanese-American Occultation Survey (TAOS) monitors fields of up to∼1000
∼
1000
stars at 5 Hz simultaneously with four small telescopes to detect occultation events from small (∼1 km
∼
1
km
...) Kuiper Belt Objects (KBOs). The survey presents a number of challenges, in particular the fact that the occultation events we are searching for are extremely rare and are typically manifested as slight flux drops for only one or two consecutive time series measurements. We have developed a statistical analysis technique to search the multi-telescope data set for simultaneous flux drops which provides a robust false-positive rejection and calculation of event significance. In this article, we describe in detail this statistical technique and its application to the TAOS data set.
We present the results of a search for occultation events by objects at distances between 100 and 1000 AU in light curves from the Taiwanese-American Occultation Survey. We searched for consecutive, ...shallow flux reductions in the stellar light curves obtained by our survey between 2005 February 7 and 2006 December 31 with a total of ~4.5 X 109 three-telescope simultaneous photometric measurements. No events were detected, allowing us to set upper limits on the number density as a function of size and distance of objects in Sedna-like orbits, using simple models.
The Taiwanese-American Occultation Survey (TAOS) project has collected more than a billion photometric measurements since 2005 January. These sky survey data--covering timescales from a fraction of a ...second to a few hundred days--are a useful source to study stellar variability. A total of 167 star fields, mostly along the ecliptic plane, have been selected for photometric monitoring with the TAOS telescopes. This paper presents our initial analysis of a search for periodic variable stars from the time-series TAOS data on one particular TAOS field, No. 151 (R.A. = 17h30m6.s7, decl. = 27?17'30'', J2000), which had been observed over 47 epochs in 2005. A total of 81 candidate variables are identified in the 3 deg2 field, with magnitudes in the range 8 < R < 16. On the basis of the periodicity and shape of the light curves, 29 variables, 15 of which were previously unknown, are classified as RR Lyrae, Cepheid, Delta *d Scuti, SX Phonencis, semi-regular, and eclipsing binaries.
We have devised an aperture photometry pipeline for data reduction of image data from the Taiwanese-American Occultation Survey (TAOS). The photometry pipeline has high computational performance, and ...is capable of real-time photometric reduction of images containing up to 1000 stars, within the sampling rate of 5 Hz. The pipeline is optimized for both speed and signal-to-noise performance, and in the latter category it performs nearly as well asDAOPHOT.This paper provides a detailed description of the TAOS aperture photometry pipeline.
The star BD +29 1748 was resolved to be a close binary from its occultation by the asteroid 87 Sylvia on 2006 December 18 UT. Four telescopes were used to observe this event at two sites separated by ...some 80 km. Two flux drops were observed at one site, whereas only one flux drop was detected at the other. From the long-term variation of Sylvia, we inferred the probable shape of the shadow during the occultation, and this in turn constrains the binary parameters: the two components of BD +29 1748 have a projected separation of 0.̋097–0.̋140 on the sky with a position angle 104°–110°. The asteroid was clearly resolved, with a size scale ranging from 130 to 290 km as projected onto the occultation direction, consistent with the size dimensions
385
×
265
×
230
km
, measured by direct adaptive optics imaging. No occultation was detected for either of the two known moonlets of 87 Sylvia.
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