Update for (309) Fraternitas - March 23/24, 2003

Jan Manek's update

                    IOTA/IOTA-ES occultation update for
          (309) Fraternitas / TYC 1887-00025-1 on March 23/24, 2003
                           visible from Russia

Summary 

In the night of March 23/24, 2003 a faint 12.3 mag star TYC 1887-00025-1 will be occulted by a 55 km asteroid (309) Fraternitas. This update is based on USNO/Flagstaff and TMO astrometry for the asteroid and recent UCAC star position.

The updated path shows ~6 path width north shift with time 1.4 minutes later compared to Edwin Goffin's nominal prediction.

Updated path runs over Russia around 23:48.0 UT at low altitudes. I suppose that this together with faint star and only 4 second maximum duration makes this event practically unobservable. Please check the path chart for details.

Clear sky and good luck !!!

The event at one glimpse:
 * date and approx. UT time of event: March 23, 2003 @ 23:48 UT (Europe)
 * magnitude of target star: 12.3
 * magnitude drop [mag]: 3.6
 * estimated maximum duration [s]: 4.0
 * path description: given above
 * Goffin's original chart reference: A03_0331

The occultation path:
 * approximate ground width [km]: 230
 * uncertainty [path widths]: 1.5
 * uncertainty in time [s]: 7
 * 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 1887-00025-1
 * constellation: Gemini
 * J2000 position [h,m,s; o,',"]: 06h 25m 37.8846s; +26o 50' 20.993"
 * position source: recent UCAC position combined with Tycho-2 proper motion
 * estimated accuracy ["]: 0.02" (0.02", 0.01")
 * V mag [mag]: 12.33
 * B-V [mag]: +0.35
 * remarks:
    Target star is in NW Gemini almost on border with Auriga, about 4.4 degrees north of 2.9 mag star
    mu Geminorum = SAO 78297.
    !!! 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: (309) Fraternitas
     approx. diameter [km]: 55
 * orbital information
     orbit source: calculation Manek
     source of used astrometry: USNO/Flagstaff (Ron Stone)
     number of used observations: 92 USNO, 20 TMO
     number of rejected observations: 20 USNO
     time covered by the observations: 1997 10 21 - 2003 03 06
     rms residuals ["] (RA,DE): 0.07", 0.07"
     estimated positional accuracy at epoch of event ["]: 0.04", 0.04"
     remarks:

Data for the event:
 * UT date and time of least geocentric approach: 23:46.5 UT
 * approx. V mag of minor planet at event [mag]: 15.9
 * geocentric parallax of minor planet ["]: 3.207
 * magnitude drop [mag]: 3.6
 * estimated maximum duration [s]: 4.0
 * apparent motion of minor planet ["/h]: 24.74
 * angular distance to moon, phase of moon [deg,%]: 163, 62%
 * remarks:

Elements for WinOccult:
============ cut here ===========================================
 2003 Mar 23
309 Fraternitas
23h 46.5m UT
87-00025-1  12.3    6 25 37.885 26 50 20.99TYC 1887-00025-1
15.9     55    4.0   2.742     1.815     -4.72
  -81.259  26.841  -174.97    1.17
 23.7744   .18362   .94989  7.57293 -1.47110  0.00581 -0.00028
2000    164.6203032003 322.00000310.638012356.6569393.721209  0.114781362.666158532.3601332410.45   0.15
RATE 2.2639930 .0000000 .0000000 .0000000 .00000000 .00000000 .00000000
============ cut here ===========================================

Calculator(s): Jan Manek









Path coordinates:
                  Center               Altitude       Path Limits
  E. Longitude   Latitude      U.T.   star   sun   Limit 1    Limit 2
   ........................... shortened .............................
      o  '  "     o  '  "    h  m  s     o     o    o  '  "    o  '  "
                                                   Latitude   Latitude
     61  0  0    74  9 45   23 46 20    14    -8   75 16 51   72 56  1
     60  0  0    73 59 57   23 46 23    14    -8   75  8 29   72 44 19
     59  0  0    73 49  9   23 46 26    14    -8   74 59 17   72 31 19
     58  0  0    73 37 15   23 46 28    14    -9   74 49 14   72 16 53
     57  0  0    73 24  8   23 46 31    14    -9   74 38 12   72  0 50
     56  0  0    73  9 40   23 46 34    14    -9   74 26  8   71 42 54
     55  0  0    72 53 39   23 46 38    14   -10   74 12 54   71 22 47
     54  0  0    72 35 53   23 46 41    14   -10   73 58 22   71  0  2
     53  0  0    72 16  3   23 46 45    14   -11   73 42 21   70 34  2
     52  0  0    71 53 46   23 46 48    14   -11   73 24 39   70  3 54
     51  0  0    71 28 30   23 46 53    14   -12   73  4 59   69 28 13
     50  0  0    70 59 29   23 46 57    13   -12   72 42 59   68 44 26
     49  0  0    70 25 31   23 47  2    13   -13   72 18  9   67 47 11
     48  0  0    69 44 38   23 47  8    13   -14   71 49 48   66 18 54
                                                  Longitude  Longitude
     46 13 38    68  0  0   23 47 22    12   -15   43 30 41   49 11 49
     45 36 29    67  0  0   23 47 29    12   -16   43  2 34   48 23 35
     45 13  6    66  0  0   23 47 36    11   -17   42 46 28   47 51 27
     45  1 33    65  0  0   23 47 42    11   -18   42 40 51   47 32 55
     45  0 23    64  0  0   23 47 48    10   -18   42 44 30   47 26 10
     45  8 32    63  0  0   23 47 54     9   -19   42 56 32   47 29 55
     45 25 12    62  0  0   23 47 59     8   -20   43 16 17   47 43 10
     45 49 50    61  0  0   23 48  4     7   -20   43 43 16   48  5 17
     46 22  3    60  0  0   23 48  8     7   -21   44 17  9   48 35 49
     47  1 39    59  0  0   23 48 12     6   -21   44 57 43   49 14 33
     47 48 34    58  0  0   23 48 15     5   -22   45 44 56   50  1 27
   ........................... 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-|
--------------------------------------------------------------------U---U---