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Updated: 2011 JUN 07, 23:06 UT
Event Rank : 46
(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 2011 Jun 19 UT, the 29 km diameter asteroid (197) Arete will occult a 12.2 mag star in the constellation Capricornus for observers along a narrow path across the North Island of New Zealand from Masterton to Coromandel. Auckland and Wellington are on the edge of the one sigma limit.
In the case of an occultation, the combined light of the asteroid and the star will drop by 1.1 mag to 12.8 mag (the magnitude of the asteroid) for at most 6.1 seconds.
This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Alice Monet, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC.
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.
Centre Star Star Sun Path Limit1 Path Limit2 Error Limit1 Error Limit2
E. Longitude Latitude U.T. Alt Az Alt
o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " o ' " o ' " o ' " o ' "
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
175 40 27 -32 36 16 16 38 17 71 290 -33 175 50 8 -32 36 0 175 30 45 -32 36 31 176 17 42 -32 35 13 175 3 17 -32 37 9
175 39 43 -33 59 37 16 38 48 71 293 -33 175 49 34 -33 59 21 175 29 52 -33 59 52 176 17 35 -33 58 32 175 1 57 -34 0 32
175 40 1 -35 23 14 16 39 20 70 297 -33 175 50 2 -35 22 57 175 30 0 -35 23 29 176 18 32 -35 22 7 175 1 36 -35 24 11
175 41 25 -36 47 8 16 39 52 69 300 -33 175 51 37 -36 46 51 175 31 13 -36 47 25 176 20 38 -36 45 59 175 2 18 -36 48 8
175 44 1 -38 11 25 16 40 23 69 303 -33 175 54 25 -38 11 7 175 33 37 -38 11 42 176 24 0 -38 10 12 175 4 8 -38 12 27
175 47 55 -39 36 6 16 40 55 68 305 -33 175 58 32 -39 35 47 175 37 19 -39 36 24 176 28 43 -39 34 50 175 7 13 -39 37 11
175 53 15 -41 1 14 16 41 27 67 307 -33 176 4 5 -41 0 55 175 42 24 -41 1 33 176 34 56 -40 59 55 175 11 40 -41 2 24
176 0 8 -42 26 54 16 41 59 66 310 -33 176 11 14 -42 26 33 175 49 3 -42 27 14 176 42 47 -42 25 30 175 17 36 -42 28 8
176 8 46 -43 53 9 16 42 30 65 311 -33 176 20 8 -43 52 47 175 57 24 -43 53 30 176 52 27 -43 51 40 175 25 11 -43 54 27
Uncertainty in time = +/- 9 secs
Prediction of 2011 Jun 8.0
Use these links for further information:
[Planetary Occultations]
[Using the Predictions]
[Observing Details]
[Timing Details]
[Reporting Details]
[Report Form]
[Asteroid Occultation Results]
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