Update for (238) Hypatia - March 5, 2000

Jan Manek's update

                  IOTA/IOTA-ES occultation update for
       (238) Hypatia / TYC 0705-00130-1 event on March 5, 2000
            visible from northern Norway, Sweden and Finland


Summary 

In the night of March 5, 2000 a 10.7 mag star TYC 0705-00130-1 will be occulted by a large 156 km asteroid (238) Hypatia. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and Tycho-2 star position.

The updated path shows ~0.5 path width south shift with time ~0.2 minutes later compared to Edwin Goffin's nominal prediction.

The path of this occultation runs over northern Norway, Sweden and Finland around 19:42 UT.

Goffin gives asteroid diameter ~77km, which is half the value I have in my data. Can't find his source so I retain the 156km value.

The event at one glimpse:
 * date and approx. UT time of event: March 5, 2000 @ 19:42 UT
 * magnitude of target star: 10.7
 * magnitude drop [mag]: 2.8
 * estimated maximum duration [s]: 10.7
 * path description: given above
 * Goffin's original chart reference: A00_0321.

The occultation path:
 * approximate ground width [km]: 200
 * uncertainty [path widths]: 1.2
 * uncertainty in time [s]: 15
 * map: below
 * remarks: Path uncertainities are given according to nominal star
    position errors and expected asteroid positional accuracy.
    !!!!!!!
    Thick line indicates the centerline for this event.
    !!!!!!!

Data for the target star:
 * name: TYC 0705-00130-1
 * constellation: Orion
 * J2000 position [h,m,s; o,',"]: 05h 31m 35.273s; +09o 31' 34.36"
 * position source: Tycho-2
 * estimated accuracy ["]: 0.06" (0.04", 0.05")
 * V mag [mag]: 10.73
 * B-V [mag]: +0.38
 * remarks: 
     Target star is in northern Orion, just 1 degree west of trio of bright 
     stars lambda, phi1 and phi2 Orionis. There is 9.5 mag star only 1.7' 
     ESE of target and 11.4 mag star 2.3' west of target.

Close finding chart (prepared in GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 2.0x2.0 degrees
 * limiting magnitude is 12.0
 * labeled stars have indicated SAO numbers





Data for the minor planet:
 * general information:
     number, name: (238) Hypatia
     approx. diameter [km]: 156
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 56 USNO, 13 TMO
     number of rejected observations: 2 USNO, 2 TMO
     time covered by the observations: 1998 07 02 - 2000 02 07
     rms residuals ["] (RA,DE): 0.05", 0.05"
     estimated positional accuracy at epoch of event ["]: 0.05"
     remarks: Goffin gives asteroid diameter ~77km, which is half the value
       I have in my data. Can't find his source so I retain the 156km value.

Data for the event:
 * UT date and time of least geocentric approach: 19:37:39 UT
 * approx. V mag of minor planet at event [mag]: 10.7
 * geocentric parallax of minor planet ["]: 3.511
 * magnitude drop [mag]: 2.8
 * estimated maximum duration [s]: 10.7
 * apparent motion of minor planet ["/h]: 28.83
 * angular distance to moon, phase of moon [deg,%]: 102, 0%
 * remarks: 

Calculator(s): Jan Manek






Path coordinates:
                                       Altitude
  E. Longitude    Latitude     U.T.    star  sun
   ........ shortened ..........................
   - 14 00 00   + 57 33 20   19 40 19   42    -9
   - 12 00 00   + 58 22 50   19 40 28   41   -10
   - 10 00 00   + 59 10 07   19 40 37   40   -11
   -  8 00 00   + 59 55 14   19 40 45   39   -12
   -  6 00 00   + 60 38 12   19 40 53   38   -13
   -  4 00 00   + 61 19 05   19 41 00   37   -14
   -  2 00 00   + 61 57 56   19 41 07   37   -15
   +  0 00 00   + 62 34 47   19 41 14   36   -15
   +  2 00 00   + 63 09 42   19 41 20   35   -16
   +  4 00 00   + 63 42 44   19 41 26   34   -17
   +  6 00 00   + 64 13 58   19 41 32   33   -17
   +  8 00 00   + 64 43 27   19 41 37   32   -18
   + 10 00 00   + 65 11 14   19 41 43   31   -18
   + 12 00 00   + 65 37 23   19 41 47   31   -19
   + 14 00 00   + 66 01 58   19 41 52   30   -19
   + 16 00 00   + 66 25 02   19 41 57   29   -20
   + 18 00 00   + 66 46 37   19 42 01   28   -20
   + 20 00 00   + 67 06 48   19 42 05   27   -21
   + 22 00 00   + 67 25 37   19 42 09   27   -21
   + 24 00 00   + 67 43 07   19 42 12   26   -22
   + 26 00 00   + 67 59 20   19 42 16   25   -22
   + 28 00 00   + 68 14 20   19 42 19   24   -22
   + 30 00 00   + 68 28 07   19 42 22   24   -23
   + 32 00 00   + 68 40 45   19 42 25   23   -23
   + 34 00 00   + 68 52 16   19 42 28   22   -23
   + 36 00 00   + 69 02 41   19 42 31   22   -23
   + 38 00 00   + 69 12 01   19 42 34   21   -24
   + 40 00 00   + 69 20 19   19 42 36   20   -24
   + 42 00 00   + 69 27 35   19 42 39   20   -24
   + 44 00 00   + 69 33 51   19 42 41   19   -24
   + 46 00 00   + 69 39 08   19 42 44   18   -25
   + 48 00 00   + 69 43 26   19 42 46   18   -25
   + 50 00 00   + 69 46 47   19 42 48   17   -25
   + 52 00 00   + 69 49 11   19 42 50   16   -25
   + 54 00 00   + 69 50 37   19 42 52   16   -25
   + 56 00 00   + 69 51 07   19 42 53   15   -25
   + 58 00 00   + 69 50 41   19 42 55   14   -26
   + 60 00 00   + 69 49 19   19 42 57   13   -26
   + 62 00 00   + 69 46 59   19 42 58   13   -26
   + 64 00 00   + 69 43 43   19 43 00   12   -26
   ........ shortened ..........................

----------------------------------------------------------------------------
Jan Manek
Stefanik Observatory                Private :
Petrin 205                          Werichova 950
118 46  Praha 1                     152 00  Praha 5 - Barrandov     |_|_|
Czech Republic                      Czech Republic                  /   \
Internet : jmanek@mbox.vol.cz                                      |-O-O-|
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