ASTROMETRIC UPDATE:
OCCULTATION BY (402) CHLOE - 2002 MAR 12
[OCCULT Prediction + Finder Charts]
UPDATE: 2002 MAR 04, 19:16 UT
THE UPDATED PATH
On March 12 U.T. (morning of March 13) the 54 km diameter asteroid (402) Chloe will occult a 10.6 mag star in the constellation Serpens for observers along a path across SE Australia and north central New Zealand.
The path is expected to cross South Australia, north central Victoria (Bendigo and Bairnsdale) and possibly southern NSW about 15:21.5 UT, and New Zealand (New Plymouth, Hawera, Wanganui, Napier, Hastings) shortly after 15:23 UT
In the case of an occultation, the combined light of the asteroid and the star will drop by 3.4 mag to 14.0 mag (the magnitude of the asteroid) for at most 3.2 seconds.
This update is based on historical astrometry from AstDys, and the UCAC and Tycho-2 catalogs for the star position.
Additional details of this and other events are available at Steve Preston's website at http://www.oz.net/~stevepr/Asteroids/asteroid.htm
EVENT DETAILS SUMMARY :
- Date and approx. UT time of event : 2002 Mar 12, ~15:21.5 UT (Australia) and ~15:23 UT (New Zealand)
(Refer to map for your own location)
- Magnitude of target star : 10.6
- Magnitude drop [mag] : 3.4
- Estimated maximum duration [s] : 3.2
- Phase of moon, angular distance : 2 % sunlit, 75° distance
- Sun : 90° distance
- Rough path description : SE Australia, N New Zealand
The Occultation Path :
- Approximate projected width [km] : 60
- Uncertainty interval [path widths] : +/- 1.20 (1 sigma)
- Uncertainty interval approx RA,DE ["] : (+/- .039 +/- .035) (1 sigma)
- Uncertainty ellipse (major, minor, PA) : ( .038", .035", 94° ) (1 sigma)
- Remarks :
Data for the target star :
- Name : TYC 5662-00770
- Constellation : Serpens
- J2000 position [h,m,s ; °,',"]: RA: 17 28 12.2340 DE: -11 01 57.197
- Position source : Pos: UCAC, pm: Tycho-2, pi:
- Standard error : RA,DE ["]: ( .030, .030 )
- V mag [mag] : 10.6
- Remarks : (none)
Data for the minor planet :
- Number, name : (402) Chloe
- Approx. diameter [km] : 54
- Approx. diameter [arcsec] : .032
- Source of used astrometry : Astdys
- Number of used observations : 368
- Number of rejected observations : 13
- Time covered by the observations : 1904 Jul 06 - 2001 Jun 02
- 1 sigma uncertainty ellipse (major, minor, PA) : 0.024, 0.018, 101°
- Remarks :
- Update computed by : Steve Preston, Medina, Washington, USA. (OrbFit).
IMPORTANT NOTE!
Astrometric updates such as these should not be taken as definitive, but rather only as an indication of where the true track may lie relative to the original predicted track. Observers must bear in mind that later astrometry, in which the target star is measured in the same field as the asteroid, may still reveal substantial changes to the predicted track and time of the event. For this reason it is most important that observers far from the predicted track still monitor the event.
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