Update for (283) Emma - March 15, 2000

Jan Manek's update

                  IOTA/IOTA-ES occultation update for
        (283) Emma / TYC 1882-01513-1 event on March 15, 2000
              visible from Russia, Khazachstan and China


Summary 

In the night March 15, 2000 a ~10.7 mag star TYC 1882-01513-1 will be occulted by a 150 km asteroid (283) Emma. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and Tycho-2 star position.

The updated path shows no path shift with time ~0.2 minutes later compared to Edwin Goffin's nominal prediction.

The path of this occultation runs over Kola peninsula ~18:52 UT, down to SE over Ural, close to Sverdlovsk and Chelyabinsk ~18:55 UT. Later it runs over Khazachstan south of Karaganda ~18:55 UT, lake Balkchas and Alma-Ata ~18:57 UT to China ~18:58 UT.

The event at one glimpse:
 * date and approx. UT time of event: March 15, 2000 @ 18:55 UT
 * magnitude of target star: 10.7
 * magnitude drop [mag]: 3.7
 * estimated maximum duration [s]: 13.3
 * path description: given above
 * Goffin's original chart reference: A00_0323

The occultation path:
 * approximate ground width [km]: 230
 * uncertainty [path widths]: 1.7
 * uncertainty in time [s]: 25
 * 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 1882-01513-1
 * constellation: Gemini
 * J2000 position [h,m,s; o,',"]: 06h 19m 58.989s; +25o 12' 07.39"
 * position source: Tycho-2  
 * estimated accuracy ["]: 0.07 (0.04", 0.06")
 * V mag [mag]: 10.74
 * B-V [mag]: +0.39
 * remarks: 
     Target star is in eastern Gemini, about 2.8 degrees north of 2.9 mag
     red variable star mui Geminorum. There is 7.1 mag star SAO 78251 
     8.6' east of target and 7.5 mag star SAO 78231 ~11.4' south of target.
     
Close finding chart (prepared in GUIDE7):
 * occulted star is in center - labeled with cross
 * field is 1.5x1.5 degrees
 * limiting magnitude is 12.5
 * labeled stars have indicated SAO numbers





Data for the minor planet:
     number, name: (283) Emma     
     approx. diameter [km]: 150
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 48 USNO, 3 TMO
     number of rejected observations: 3 USNO
     time covered by the observations: 1998 07 16 - 2000 02 07
     rms residuals ["] (RA,DE): 0.08", 0.06"
     estimated positional accuracy at epoch of event ["]: 0.07"
     remarks: 

Data for the event:
 * UT date and time of least geocentric approach: 18:52.4  UT
 * approx. V mag of minor planet at event [mag]: 14.4
 * geocentric parallax of minor planet ["]: 3.083
 * magnitude drop [mag]: 3.7
 * estimated maximum duration [s]: 13.3
 * apparent motion of minor planet ["/h]: 19.68
 * angular distance to moon, phase of moon [deg,%]: 23, 77%
 * remarks: 

Calculator(s): Jan Manek





Path coordinates:
                                       Altitude
  E. Longitude    Latitude     U.T.    star  sun
      o  '  "     o  '  "    h  m  s     o     o
   ........ shortened ..........................
     24  0  0    73  9 19   18 51 25    40   -11
     26  0  0    72 35 18   18 51 33    40   -12
     28  0  0    71 58 54   18 51 42    40   -13
     30  0  0    71 20  2   18 51 51    40   -14
     32  0  0    70 38 32   18 52  0    41   -15
     34  0  0    69 54 18   18 52 10    41   -16
     36  0  0    69  7 12   18 52 21    41   -17
     38  0  0    68 17  9   18 52 32    41   -18
     40  0  0    67 24  4   18 52 43    41   -19
     42  0  0    66 27 52   18 52 55    41   -20
     44  0  0    65 28 32   18 53  8    40   -22
     46  0  0    64 26  3   18 53 21    40   -23
     48  0  0    63 20 27   18 53 35    40   -24
     50  0  0    62 11 47   18 53 50    39   -26
     52  0  0    61  0  9   18 54  4    39   -27
     54  0  0    59 45 44   18 54 20    38   -29
     56  0  0    58 28 42   18 54 35    38   -31
     58  0  0    57  9 16   18 54 51    37   -32
     60  0  0    55 47 43   18 55  7    36   -34
     62  0  0    54 24 21   18 55 23    35   -36
     64  0  0    52 59 28   18 55 39    34   -38
     66  0  0    51 33 24   18 55 54    32   -39
     68  0  0    50  6 32   18 56 10    31   -41
     70  0  0    48 39 11   18 56 25    30   -43
     72  0  0    47 11 43   18 56 40    28   -44
     74  0  0    45 44 28   18 56 54    27   -46
     76  0  0    44 17 47   18 57  7    25   -48
     78  0  0    42 51 57   18 57 20    23   -49
     80  0  0    41 27 17   18 57 32    21   -50
     82  0  0    40  4  2   18 57 43    19   -52
     84  0  0    38 42 28   18 57 53    17   -53
     86  0  0    37 22 46   18 58  2    15   -54
     88  0  0    36  5 10   18 58 10    14   -54
     90  0  0    34 49 49   18 58 16    12   -55
     92  0  0    33 36 53   18 58 22     9   -56
     94  0  0    32 26 28   18 58 27     7   -56
   ........ 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-|
--------------------------------------------------------------------U---U---