Update for (287) Nephthys - June 3/4, 2003

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
            (287) Nephthys / TYC 1397-01488 on June 3/4, 2003
               visible from S France, NE Spain and Sardinia

Summary 

In the night of June 3/4, 2003 a faint 11.3 mag star TYC 1397-01488 will be occulted by a 70 km asteroid (287) Nephthys. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and recent UCAC star position.

The updated path shows ~1.0 path width north shift with no time correction compared to Eric Frappa's nominal prediction.

Updated path runs over S France around 21:53.9 UT, NE Spain ~21:54.0 and Sardinia ~21:54.1 UT. Please check the path chart for details.

Please pay attention to possible satellite of Nephthys (as mentioned by Jean Lecacheux) so observers up to ~500km from main body path should try to observe. On assumption that satellite's size is ~1/10 of main body, the duration will be very short; under 0.2 second. Video observations or CCD drift scans are highly desirable in this case.

Orbit used for this update is the same as the one used for April 28th event which had no occultation on central line. It is hard to say what was the reason of the shift and where to try this time. If I should expect any shift - then probably a south shift within uncertainty, but please don't shoot at me ...

Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: June 3, 2003 @ 21:54 UT (Europe)
 * magnitude of target star: 11.3
 * magnitude drop [mag]: 2.2
 * estimated maximum duration [s]: 2.2
 * path description: given above
 * Goffin's original chart reference: none

The occultation path:
 * approximate ground width [km]: 110
 * uncertainty [path widths]: 1.0
 * uncertainty in time [s]: 2
 * map: below
 * remarks: Path uncertainties are given according to nominal star
    position errors and expected asteroid positional accuracy.

Data for the target star:
 * name: TYC 1397-01488
 * constellation: Cancer
 * J2000 position [h,m,s; o,',"]: 09h 01m 36.1437s; +18o 46' 51.608"
 * position source: recent UCAC position combined with Tycho-2 proper motion
 * estimated accuracy ["]: 0.03" (0.02", 0.02")
 * V mag [mag]: 11.27
 * B-V [mag]: +0.37
 * remarks:
    Recent UCAC position was provided by Marion and Norbert Zacharias.
    Target star is in middle Cancer, just east of open cluster M44 or 1.2 degree north
    of Jupiter. Should be easy to find.
    There is 11.0 mag star just 1.6' north of target star.
    !!! IMPORTANT !!!
    Purple stars in identification chart are so called 'non-star' objects in GSC; in dense fields
    the 'non-stars' are often real stars or blends of close pairs. Be careful about this.

Close finding chart (prepared in GUIDE8):
 * occulted star is in center - labeled with cross
 * field is 3.0x3.0 degrees
 * limiting magnitude is 12.5
 * labeled stars have indicated SAO numbers
 * remarks: Second chart is 30' blowup to show correctly the target star in the field.











Data for the minor planet:
 * general information:
     number, name: (287) Nephthys
     approx. diameter [km]: 70
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone), TMO (Bill Owen)
     number of used observations: 110 USNO, 43 TMO
     number of rejected observations: 17 USNO, 8 TMO
     time covered by the observations: 1997 05 22 - 2003 03 26
     rms residuals ["] (RA,DE): 0.05", 0.05"
     estimated positional accuracy at epoch of event ["]: 0.03", 0.03"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 21:52.0 UT
 * approx. V mag of minor planet at event [mag]: 13.3
 * geocentric parallax of minor planet ["]: 3.239
 * magnitude drop [mag]: 2.2
 * estimated maximum duration [s]: 2.2
 * apparent motion of minor planet ["/h]: 59.31
 * angular distance to moon, phase of moon [deg,%]: 18, 13%
 * remarks:

Elements for WinOccult:
============ cut here ===========================================
 2003 Jun 03
287 Nephthys
21h 52.0m UT
97-01488-1  11.3    9  1 36.144 18 46 51.61TYC 1397-01488-1
13.3     70    2.2   2.715     4.066    -11.89
  -84.538  18.785  -148.46   22.35
 21.8666   .15409   .75107 17.82723 -3.66952  0.00449 -0.00124
2000    254.4863882003 531.00000118.809665142.49400410.023480 0.023512932.353656712.298315358.305   0.22
RATE 2.7295400 .0000000 .0000000 .0000000 .00000000 .00000000 .00000000
============ cut here ===========================================

Calculator(s): Jan Manek









Path coordinates:
                  Centre              Star  Star   Sun      Path Limits           Error Limits
  E. Longitude   Latitude      U.T.    Alt    Az   Alt    Limit 1    Limit 2    Limit 3    Limit 4
                                                         Latitude   Latitude   Latitude   Latitude
   ........................................ shortened ............................................
      o  '  "     o  '  "    h  m  s     o     o     o    o  '  "    o  '  "    o  '  "    o  '  "
  - 20  0  0    53  1 48   21 53 19    30   262    -3   52 25 31   53 38 38   51 14 35   54 54 10
   - 19  0  0    52 35 38   21 53 21    29   263    -3   51 59 25   53 12 26   50 48 33   54 27 52
   - 18  0  0    52  9 19   21 53 23    29   264    -4   51 33  9   52 46  4   50 22 22   54  1 24
   - 17  0  0    51 42 52   21 53 25    28   265    -5   51  6 45   52 19 34   49 56  4   53 34 46
   - 16  0  0    51 16 17   21 53 27    28   266    -6   50 40 13   51 52 55   49 29 39   53  8  0
   - 15  0  0    50 49 35   21 53 29    27   267    -6   50 13 35   51 26  9   49  3  8   52 41  6
   - 14  0  0    50 22 48   21 53 31    26   268    -7   49 46 51   50 59 17   48 36 32   52 14  5
   - 13  0  0    49 55 55   21 53 32    26   269    -8   49 20  3   50 32 20   48  9 51   51 46 58
   - 12  0  0    49 28 58   21 53 34    25   270    -9   48 53 11   50  5 19   47 43  8   51 19 46
   - 11  0  0    49  1 58   21 53 36    24   271    -9   48 26 16   49 38 14   47 16 22   50 52 30
   - 10  0  0    48 34 56   21 53 38    24   272   -10   47 59 19   49 11  6   46 49 35   50 25 11
   -  9  0  0    48  7 53   21 53 40    23   273   -11   47 32 21   48 43 58   46 22 47   49 57 50
   -  8  0  0    47 40 50   21 53 41    22   274   -12   47  5 23   48 16 49   45 56  0   49 30 29
   -  7  0  0    47 13 47   21 53 43    22   275   -13   46 38 27   47 49 40   45 29 14   49  3  7
   -  6  0  0    46 46 47   21 53 45    21   275   -13   46 11 32   47 22 33   45  2 30   48 35 47
   -  5  0  0    46 19 49   21 53 46    20   276   -14   45 44 40   46 55 29   44 35 50   48  8 29
   -  4  0  0    45 52 54   21 53 48    19   277   -15   45 17 52   46 28 28   44  9 14   47 41 13
   -  3  0  0    45 26  5   21 53 49    19   278   -16   44 51  9   46  1 31   43 42 43   47 14  2
   -  2  0  0    44 59 21   21 53 51    18   279   -16   44 24 31   45 34 40   43 16 18   46 46 56
   -  1  0  0    44 32 43   21 53 52    17   280   -17   43 58  1   45  7 56   42 50  0   46 19 57
      0  0  0    44  6 13   21 53 53    16   280   -18   43 31 38   44 41 18   42 23 50   45 53  4
      1  0  0    43 39 52   21 53 55    16   281   -19   43  5 23   44 14 49   41 57 49   45 26 20
      2  0  0    43 13 39   21 53 56    15   282   -19   42 39 18   43 48 30   41 31 57   44 59 44
      3  0  0    42 47 37   21 53 57    14   283   -20   42 13 23   43 22 20   41  6 16   44 33 19
      4  0  0    42 21 47   21 53 58    13   283   -21   41 47 40   42 56 22   40 40 46   44  7  4
      5  0  0    41 56  8   21 53 59    12   284   -21   41 22  8   42 30 36   40 15 29   43 41  1
      6  0  0    41 30 42   21 54  0    12   285   -22   40 56 50   42  5  2   39 50 24   43 15 11
      7  0  0    41  5 30   21 54  1    11   286   -23   40 31 45   41 39 42   39 25 33   42 49 35
      8  0  0    40 40 32   21 54  2    10   286   -24   40  6 55   41 14 37   39  0 57   42 24 13
      9  0  0    40 15 50   21 54  3     9   287   -24   39 42 20   40 49 47   38 36 36   41 59  7
     10  0  0    39 51 23   21 54  3     8   288   -25   39 18  1   40 25 13   38 12 31   41 34 16
     11  0  0    39 27 14   21 54  4     7   288   -26   38 53 59   40  0 55   37 48 43   41  9 43
     12  0  0    39  3 22   21 54  4     6   289   -26   38 30 15   39 36 56   37 25 13   40 45 27
     13  0  0    38 39 49   21 54  5     6   290   -27   38  6 48   39 13 15   37  2  1   40 21 29
     14  0  0    38 16 34   21 54  5     5   290   -27   37 43 41   38 49 53   36 39  7   39 57 51
     15  0  0    37 53 39   21 54  6     4   291   -28   37 20 54   38 26 50   36 16 34   39 34 33
     16  0  0    37 31  5   21 54  6     3   291   -29   36 58 27   38  4  8   35 54 20   39 11 35
     17  0  0    37  8 52   21 54  6     2   292   -29   36 36 20   37 41 47   35 32 27   38 48 58
     18  0  0    36 47  0   21 54  6     1   293   -30   36 14 35   37 19 48   35 10 56   38 26 43
   ........................................ shortened ............................................

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