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Updated: 2019 Jul 21, 06:35 UT
Event Rank : 75
(The event Rank is a measure of the likelihood of observing an event, and is equal to the probability of at least one successful observation by a team of two observers spaced 1/8 path width just inside opposite sides of the predicted path. An event rank of 100 indicates that the prediction is expected to be very accurate).
THE UPDATED PATH
Note: The duration given in the line below is the interval during which the occultation shadow sweeps across the Earth - please see the minute markers on the map to determine the approximate time for your location.
On 2019 Oct 11 UT, the 41 km diameter asteroid (332) Siri will occult a 12.2 mag star in the constellation Taurus for observers along a slightly uncertain path across north-eastern Tasmania, Victoria, South Australia and West Australia, passing over Melbourne and Adelaide.
In the case of an occultation, the combined light of the asteroid and the star will drop by 2.25 mag to 14.28 mag (the magnitude of the asteroid) for at most 18.5 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, astrometry for the asteroid kindly provided by Bill Owen, astrometry for the asteroid kindly provided by the IAU Minor Planet Center. This work has made use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, http://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
Additional details of this and other events are available at Steve Preston's website at http://www.asteroidoccultation.com/
EVENT DETAILS SUMMARY :Important Note regarding Accuracy:
The uncertainty interval in path widths given above (and shown as a 1-sigma uncertainty ellipse on the plot) refers to RMS deviation and is applied as a +/- range. In other words, a path uncertainty of 1.0 path widths means that the actual center of the asteroid's shadow path should fall within plus or minus 1 path width of the plotted path center. However path errors larger than 1 sigma have been observed so observers should be alert for primary occultations within plus or minus 3 sigma of the updated path.
Further, almost all asteroidal satellites discovered so far have been found within 10 diameters of the asteroid (since this distance is deep enough within the gravitational well to be stable over long timescales). Therefore, if monitoring for secondary events, observing out to about 10 path-widths either side of the predicted track remains worthwhile.
We therefore recommend that you monitor for events if your observing location is up to +/- 10 path-widths from the predicted track. If not monitoring for occultations by secondary bodies you should observe from locations within 3 sigma of the nominal path.
In terms of time, the predictions are now usually accurate to about +/- 0.3 minute so you should be most attentive during the predicted minute of the event. However if intending to catch a potential satellite occultation you should start observing at least 10 times the predicted central duration before the predicted closest approach time for your location, and continue for a similar period afterwards.
Occultation of UCAC4-567-010918 by 332 Siri on 2019 Oct 11
Centre Star Star Sun Path Limits Error Limits Alt
E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4 Crn
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' "
Longitude Longitude Longitude Longitude
153 5 25 -44 0 0 16 25 26 22 9 -26 153 48 42 152 21 37 154 39 53 151 28 28 1.85
151 50 28 -43 0 0 16 26 15 23 10 -27 152 33 58 151 6 25 153 25 23 150 12 57 1.85
150 32 24 -42 0 0 16 27 7 24 11 -29 151 16 13 149 48 1 152 7 58 148 54 6 1.84
149 11 0 -41 0 0 16 28 2 25 12 -30 149 55 14 148 26 11 150 47 26 147 31 41 1.83
147 46 4 -40 0 0 16 29 0 25 14 -31 148 30 49 147 0 41 149 23 35 146 5 29 1.82
146 17 18 -39 0 0 16 30 1 26 15 -33 147 2 41 145 31 14 147 56 10 144 35 9 1.82
144 44 23 -38 0 0 16 31 6 27 17 -34 145 30 32 143 57 29 146 24 54 143 0 18 1.81
143 6 54 -37 0 0 16 32 14 28 18 -35 143 54 0 142 18 59 144 49 24 141 20 30 1.80
141 24 22 -36 0 0 16 33 26 28 20 -37 142 12 37 140 35 13 143 9 17 139 35 9 1.79
139 36 10 -35 0 0 16 34 42 29 21 -39 140 25 48 138 45 33 141 24 1 137 43 32 1.78
137 41 34 -34 0 0 16 36 3 29 23 -40 138 32 53 136 49 8 139 32 57 135 44 44 1.77
135 39 34 -33 0 0 16 37 29 29 25 -42 136 32 57 134 44 53 137 35 17 133 37 31 1.76
134 0 0 -32 13 54 16 38 39 30 26 -43 -31 48 51 -32 39 19 -31 19 20 -33 10 18 1.76
133 0 0 -31 47 20 16 39 20 30 27 -44 -31 22 32 -32 12 29 -30 53 19 -32 43 7 1.75
132 0 0 -31 21 40 16 40 2 30 28 -45 -30 57 6 -31 46 34 -30 28 9 -32 16 53 1.75
131 0 0 -30 56 52 16 40 44 30 29 -45 -30 32 33 -31 21 33 -30 3 51 -31 51 34 1.75
130 0 0 -30 32 58 16 41 25 30 30 -46 -30 8 51 -30 57 25 -29 40 24 -31 27 9 1.74
129 0 0 -30 9 55 16 42 6 30 31 -47 -29 46 0 -30 34 10 -29 17 47 -31 3 39 1.74
128 0 0 -29 47 44 16 42 47 30 32 -48 -29 24 0 -30 11 47 -28 56 0 -30 41 1 1.74
127 0 0 -29 26 24 16 43 28 30 33 -48 -29 2 51 -29 50 16 -28 35 2 -30 19 16 1.73
126 0 0 -29 5 54 16 44 8 29 33 -49 -28 42 31 -29 29 36 -28 14 54 -29 58 23 1.73
125 0 0 -28 46 15 16 44 48 29 34 -50 -28 23 1 -29 9 46 -27 55 34 -29 38 22 1.73
124 0 0 -28 27 25 16 45 28 29 35 -50 -28 4 19 -28 50 48 -27 37 3 -29 19 12 1.73
123 0 0 -28 9 25 16 46 7 29 36 -51 -27 46 27 -28 32 39 -27 19 20 -29 0 52 1.73
122 0 0 -27 52 14 16 46 46 29 37 -51 -27 29 24 -28 15 20 -27 2 25 -28 43 24 1.72
121 0 0 -27 35 52 16 47 25 29 38 -52 -27 13 9 -27 58 51 -26 46 18 -28 26 46 1.72
120 0 0 -27 20 19 16 48 4 28 38 -53 -26 57 42 -27 43 12 -26 30 59 -28 10 58 1.72
119 0 0 -27 5 34 16 48 41 28 39 -53 -26 43 4 -27 28 21 -26 16 27 -27 56 0 1.72
118 0 0 -26 51 39 16 49 19 28 40 -54 -26 29 13 -27 14 20 -26 2 43 -27 41 51 1.72
117 0 0 -26 38 31 16 49 56 27 41 -54 -26 16 11 -27 1 8 -25 49 46 -27 28 33 1.72
116 0 0 -26 26 13 16 50 33 27 41 -55 -26 3 57 -26 48 44 -25 37 37 -27 16 4 1.72
115 0 0 -26 14 43 16 51 9 27 42 -55 -25 52 31 -26 37 10 -25 26 15 -27 4 25 1.72
114 0 0 -26 4 1 16 51 45 26 43 -55 -25 41 52 -26 26 25 -25 15 41 -26 53 35 1.73
113 0 0 -25 54 8 16 52 20 26 44 -56 -25 32 2 -26 16 29 -25 5 55 -26 43 35 1.73
112 0 0 -25 45 3 16 52 55 26 44 -56 -25 23 0 -26 7 21 -24 56 56 -26 34 24 1.73
Uncertainty in time = +/- 16 secs
Prediction of 2019 Jul 21.0
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