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Updated: 2017 Mar 14, 17:00 UT
Event Rank : 42
(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 2017 Apr 08 UT, the 64 km diameter asteroid (4867) Polites will occult a 10.7 mag star in the constellation Cancer for observers along a large uncertainty path across central Queensland, passing over Townsville, then across western New South Wales, passing near Broken Hill, Mildura, Millicent and Mount Gambier.
In the case of an occultation, the combined light of the asteroid and the star will drop by 6.70 mag to 17.40 mag (the magnitude of the asteroid) for at most 7.3 seconds.
This update is based on, 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 TYC 1951-01115-1 by 4867 Polites on 2017 Apr 8
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
137 50 55 -45 0 0 10 46 16 22 2 -25 137 23 32 138 18 20 135 37 37 140 5 6 0.44
138 9 26 -44 0 0 10 46 10 23 1 -26 137 42 29 138 36 25 135 58 15 140 21 30 0.44
138 28 4 -43 0 0 10 46 5 24 1 -26 138 1 32 138 54 39 136 18 53 140 38 8 0.44
138 46 49 -42 0 0 10 45 59 25 1 -27 138 20 40 139 13 1 136 39 32 140 55 0 0.44
139 5 42 -41 0 0 10 45 53 26 1 -27 138 39 55 139 31 32 137 0 12 141 12 5 0.44
139 24 44 -40 0 0 10 45 47 27 0 -28 138 59 18 139 50 12 137 20 56 141 29 25 0.44
139 43 54 -39 0 0 10 45 40 28 0 -28 139 18 47 140 9 2 137 41 42 141 46 58 0.44
140 3 13 -38 0 0 10 45 33 29 360 -29 139 38 25 140 28 3 138 2 33 142 4 46 0.45
140 22 42 -37 0 0 10 45 27 30 359 -29 139 58 12 140 47 14 138 23 28 142 22 48 0.45
140 42 21 -36 0 0 10 45 19 31 359 -30 140 18 8 141 6 36 138 44 29 142 41 6 0.45
141 2 10 -35 0 0 10 45 12 32 359 -30 140 38 13 141 26 10 139 5 36 142 59 38 0.45
141 22 11 -34 0 0 10 45 4 33 358 -31 140 58 28 141 45 55 139 26 50 143 18 25 0.45
141 42 23 -33 0 0 10 44 57 34 358 -31 141 18 55 142 5 53 139 48 11 143 37 28 0.45
142 2 46 -32 0 0 10 44 49 35 358 -32 141 39 32 142 26 3 140 9 40 143 56 46 0.45
142 23 23 -31 0 0 10 44 40 36 357 -32 142 0 20 142 46 27 140 31 18 144 16 21 0.45
142 44 11 -30 0 0 10 44 32 37 357 -32 142 21 21 143 7 4 140 53 5 144 36 12 0.45
143 5 13 -29 0 0 10 44 23 38 356 -33 142 42 34 143 27 55 141 15 2 144 56 20 0.45
143 26 29 -28 0 0 10 44 15 39 356 -33 143 4 1 143 49 0 141 37 9 145 16 44 0.45
143 47 59 -27 0 0 10 44 6 40 356 -34 143 25 41 144 10 20 141 59 27 145 37 26 0.45
144 9 44 -26 0 0 10 43 56 41 355 -34 143 47 34 144 31 56 142 21 57 145 58 26 0.45
144 31 44 -25 0 0 10 43 47 42 355 -35 144 9 43 144 53 47 142 44 39 146 19 44 0.45
144 53 59 -24 0 0 10 43 37 43 354 -35 144 32 6 145 15 54 143 7 34 146 41 21 0.45
145 16 31 -23 0 0 10 43 27 44 354 -36 144 54 45 145 38 18 143 30 42 147 3 17 0.45
145 39 19 -22 0 0 10 43 18 45 353 -36 145 17 40 146 1 0 143 54 4 147 25 32 0.45
146 2 24 -21 0 0 10 43 7 46 353 -37 145 40 52 146 23 59 144 17 40 147 48 7 0.44
146 25 48 -20 0 0 10 42 57 47 352 -37 146 4 21 146 47 17 144 41 32 148 11 3 0.44
146 49 30 -19 0 0 10 42 46 48 351 -37 146 28 8 147 10 54 145 5 39 148 34 20 0.44
147 13 31 -18 0 0 10 42 36 48 351 -38 146 52 14 147 34 50 145 30 3 148 57 59 0.44
147 37 51 -17 0 0 10 42 25 49 350 -38 147 16 39 147 59 6 145 54 44 149 22 0 0.44
148 2 32 -16 0 0 10 42 14 50 349 -39 147 41 23 148 23 44 146 19 43 149 46 24 0.44
148 27 34 -15 0 0 10 42 2 51 348 -39 148 6 28 148 48 43 146 45 1 150 11 11 0.44
Uncertainty in time = +/- 18 secs
Prediction of 2017 Mar 14.0
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