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Updated: 2019 Jul 21, 06:17 UT
Event Rank : 74
(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 04 UT, the 77 km diameter asteroid (501) Urhixidur will occult a 10.6 mag star in the constellation Perseus for observers along a somewhat uncertain path across northern South Australia and Northern Territory.
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.68 mag to 14.19 mag (the magnitude of the asteroid) for at most 7.2 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 TYC 2871-02390-1 by 501 Urhixidur on 2019 Oct 4
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
134 43 41 -37 0 0 17 23 1 11 7 -35 135 13 30 134 13 46 135 50 20 133 36 29 -0.52
134 44 9 -36 0 0 17 23 3 12 7 -36 135 13 35 134 14 37 135 49 57 133 37 48 -0.53
134 43 53 -35 0 0 17 23 5 13 7 -37 135 12 57 134 14 43 135 48 53 133 38 20 0.53
134 42 54 -34 0 0 17 23 8 14 7 -37 135 11 38 134 14 4 135 47 9 133 38 8 0.53
134 41 15 -33 0 0 17 23 11 15 7 -38 135 9 39 134 12 44 135 44 47 133 37 11 0.53
134 38 55 -32 0 0 17 23 14 16 7 -39 135 7 1 134 10 42 135 41 47 133 35 32 0.53
134 35 56 -31 0 0 17 23 17 17 7 -39 135 3 46 134 8 1 135 38 10 133 33 13 0.54
134 32 20 -30 0 0 17 23 20 18 7 -40 134 59 54 134 4 41 135 33 58 133 30 13 0.54
134 28 7 -29 0 0 17 23 24 19 7 -40 134 55 26 134 0 43 135 29 11 133 26 34 0.54
134 23 18 -28 0 0 17 23 28 20 7 -41 134 50 22 133 56 8 135 23 50 133 22 18 0.54
134 17 54 -27 0 0 17 23 32 21 7 -42 134 44 45 133 50 58 135 17 57 133 17 24 0.54
134 11 56 -26 0 0 17 23 36 22 7 -42 134 38 34 133 45 12 135 11 30 133 11 54 0.54
134 5 23 -25 0 0 17 23 40 22 7 -43 134 31 50 133 38 51 135 4 31 133 5 48 0.54
133 58 18 -24 0 0 17 23 44 23 8 -44 134 24 33 133 31 57 134 57 1 132 59 7 0.54
133 50 39 -23 0 0 17 23 49 24 8 -44 134 16 44 133 24 28 134 48 59 132 51 51 0.54
133 42 28 -22 0 0 17 23 54 25 8 -45 134 8 23 133 16 27 134 40 27 132 44 2 0.54
133 33 44 -21 0 0 17 23 59 26 8 -45 133 59 31 133 7 52 134 31 23 132 35 38 0.54
133 24 29 -20 0 0 17 24 4 27 8 -46 133 50 7 132 58 45 134 21 50 132 26 41 0.54
133 14 42 -19 0 0 17 24 10 28 8 -47 133 40 13 132 49 5 134 11 46 132 17 11 0.54
133 4 23 -18 0 0 17 24 15 29 9 -47 133 29 47 132 38 53 134 1 12 132 7 7 0.54
132 53 33 -17 0 0 17 24 21 30 9 -48 133 18 51 132 28 9 133 50 8 131 56 31 0.54
132 42 11 -16 0 0 17 24 27 31 9 -48 133 7 23 132 16 53 133 38 33 131 45 22 0.54
132 30 17 -15 0 0 17 24 33 32 9 -49 132 55 25 132 5 4 133 26 29 131 33 39 0.54
132 17 52 -14 0 0 17 24 39 33 10 -50 132 42 56 131 52 44 133 13 54 131 21 24 0.54
132 4 56 -13 0 0 17 24 46 34 10 -50 132 29 55 131 39 51 133 0 49 131 8 35 0.54
131 51 27 -12 0 0 17 24 53 35 10 -51 132 16 24 131 26 25 132 47 14 130 55 14 0.54
131 37 26 -11 0 0 17 24 59 36 10 -51 132 2 20 131 12 27 132 33 7 130 41 19 0.54
131 22 53 -10 0 0 17 25 6 37 11 -52 131 47 45 130 57 56 132 18 30 130 26 49 0.54
Uncertainty in time = +/- 5 secs
Prediction of 2019 Jul 21.0
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