Geoscience Reference
In-Depth Information
1
1
0.98
5:1
0.8
0.95
0.8
0.9
2:1
0.8
0.7
5:4
0.6
0.6
0.6
0
1:1
0.4
0.4
0.2
0.2
0
0
0
0.2
0.4
0.6
0.8
1
0
0.2
0.4
0.6
0.8
1
(Normalized) Secant or Occultation Duration
(Normalized) Secant or Occultation Duration
Fig. 5. Cumulative probability of the normalized geometric occultation duration for
a given two-dimensional shape at a certain distance. The orientation is randomly dis-
tributed with a specific direction of shadow velocity. Target star is assumed as a point
source. These are simulated results with one million events involved in each curve. The
binning factor in these (cumulative) histograms is 1000. The maximum differential prob-
abilities happen at the maximum slopes of these curves. (Left) Cumulative probability for
ellipses of different eccentricities (Starting from the leftmost curve, the eccentricities are
0.98, 0.95, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, and 0, respectively). The occultation duration
is normalized with respect to its major axis. The maximum slope in each curve is asso-
ciated with its minor axis. The slopes at the maximum occultation duration are related
to the complete elliptic integral of the second kind. (Right) Cumulative probability for
rectangles with different length to width ratios. The occultation duration is normalized
with respect to its diagonal. Two maximum slopes in each curve are associated with its
length and its width. The slopes of the straight lines range between 1
/
√
2(forsquare)
and 1 (if length
width).
seen in Fig. 5. These two points degenerate for a square shadow. However, it
is not clear whether these results can be applied while diffraction is consid-
ered. By assuming theoretical distributions with enough computing power,
ensembles of light curves can be generated systematically. To get larger or
non-spherical objects involved will require extending the existing code.
4. Perspectives
Photometry of zipper mode data is something new that the TAOS project
has developed. Synchronization of the data coming from all telescopes is
one of the major features in this experiment. We are planning to apply
the “rank statistics”
17
,
18
method to eliminate a statistical false positive.
This way, a simultaneous dip in the data from all telescopes can be given
a probability of detection and compared against the chance occurrence of
