Orbit Fit and Astrometric record for 98WS31

The following information shows the result of the orbit fit based on Gary Bernstein's method. Most of the information should be self-explanatory. Take special note that while the original Bernstein software works with barycentric coordinates, we convert these results into a heliocentric coordinate system.

# Object: 98WS31    
# Created Wed Oct 18 01:36:59 2017
# Orbit generated from Bernstein formalism
# Fitting   30 observations of   30
# Arc:  17.21y
# First observation: 1998/11/18
#  Last observation: 2016/02/04
Preliminary a, adot, b, bdot, g, gdot:
  -0.007568   0.043664  -0.000761   0.004816   0.023963   0.000000
# WARNING MRQMIN stopped after  13 iterations -- oscilliatory solution
# Chi-squared of fit:  9999.99 DOF:   54 RMS: 99.99
# Min/Max residuals: -2049.01  761.13
# Exact a, adot, b, bdot, g, gdot:
 -2.272532E-03  4.018964E-02 -2.203439E-04  4.423483E-03  2.915049E-02 -3.231772E-03
# Covariance matrix:
  1.5315E-13 -4.4065E-14  6.2426E-15 -3.9746E-15  1.1226E-13 -6.1289E-14
 -4.4065E-14  2.2706E-14 -3.4946E-15  2.3266E-15 -4.6690E-14  3.4835E-14
  6.2426E-15 -3.4946E-15  8.5215E-14 -7.9850E-15  8.9842E-15 -5.7954E-15
 -3.9746E-15  2.3266E-15 -7.9850E-15  1.7463E-15 -4.9882E-15  3.8145E-15
  1.1226E-13 -4.6690E-14  8.9842E-15 -4.9882E-15  2.7782E-13 -8.4421E-14
 -6.1289E-14  3.4835E-14 -5.7954E-15  3.8145E-15 -8.4421E-14  5.7542E-14
#      lat0       lon0       xBary       yBary       zBary        JD0
    2.641138   37.660085   -0.309438    0.042821   -0.933604  2451135.598851
# Heliocentric elements and errors
Epoch:              2451130.5000  =  1998/11/13
Mean Anomaly:          358.99378 +/-     0.001
Argument of Peri:       32.08905 +/-     0.001
Long of Asc Node:       15.81629 +/-     0.000
Inclination:             6.74098 +/-     0.000
Eccentricity:         0.73662401 +/-    0.0001
Semi-Major Axis:    133.00331634 +/-    0.0526
Time of Perihelion: 2452696.4612 +/-       0.2
Perihelion:          35.02987964 +/-    0.0191
Aphelion:           230.97675304 +/-    0.0923
Period (y)             1533.9172 +/-      0.91
# Ecliptic coordinates at JD0 (AU and AU/d)
Ecliptic X           27.73557667 +/-    0.0005
Ecliptic Y           21.69087511 +/-    0.0004
Ecliptic Z            1.57324433 +/-    0.0000
Ecliptic XDOT        -0.00256201 +/-    0.0000
Ecliptic YDOT         0.00280036 +/-    0.0000
Ecliptic ZDOT         0.00040100 +/-    0.0000
# Distances at JD0 (AU)
Heliocenter to KBO   35.24530286 +/-    0.0005
Geocenter to KBO     34.30483304 +/-    0.0006
# Hcoef:  7.78

The following table shows the complete astrometric record for 98WS31. The first three columns show the date of observation. The next six columns are RA and DEC. The next column (when provided) is the observed magnitude and filter. The next column is the object name (98WS31) followed by the observatory code and reference code for the source of the astrometry.

1998 11  18.09812  02 17 37.85   +16 33 43.0   22.5R 98WS31    695   a3608      
1998 11  18.16698  02 17 37.44   +16 33 41.4         98WS31    695   a3608      
1998 11  18.24713  02 17 36.96   +16 33 39.1         98WS31    695   a3608      
1998 12  17.84201  02 15 13.98   +16 21 24.9   23.1R 98WS31    950   a3608      
1998 12  17.87639  02 15 13.85   +16 21 24.2         98WS31    950   a3608      
1998 12  17.91186  02 15 13.72   +16 21 23.7         98WS31    950   a3608      
1999 11  30.19125  02 25 14.98   +17 27 05.5   22.8R 98WS31    695  Ca8499      
1999 11  30.19836  02 25 14.98   +17 27 05.1   22.7R 98WS31    695  Ca8499      
1999 11  30.30921  02 25 14.37   +17 27 02.3   22.4R 98WS31    695  Ca8499      
1999 11  30.31631  02 25 14.34   +17 27 02.0   22.6R 98WS31    695  Ca8499      
2000 01  02.15602  02 23 07.83   +17 15 47.1   23.3R 98WS31    697  Ca8499      
2000 01  02.20304  02 23 07.62   +17 15 46.0   23.2R 98WS31    697  Ca8499      
2000 01  02.22104  02 23 07.72   +17 15 46.0         98WS31    568  Ca8499      
2000 01  02.23592  02 23 07.69   +17 15 45.7   23.2R 98WS31    568  Ca8499      
2000 01  02.24998  02 23 07.65   +17 15 45.5         98WS31    568  Ca8499      
2000 01  03.23913  02 23 05.61   +17 15 33.3   23.1R 98WS31    697  Ca8499      
2000 01  05.11914  02 23 02.19   +17 15 10.8   23.2R 98WS31    697  Ca8499      
2000 01  05.18084  02 23 02.09   +17 15 10.0   23.1R 98WS31    697  Ca8499      
2002 09  11.39596  02 59 14.29   +20 39 18.5   22.2R 98WS31    662  Cg2658      
2002 09  11.49551  02 59 14.06   +20 39 17.8         98WS31    662  Cg2658      
2008 10  22.31914  03 52 05.54   +25 09 17.3   24.6r 98WS31    695  C~0gLs      
2008 10  22.40810  03 52 05.01   +25 09 16.7   23.6r 98WS31    695  C~0gLs      
2008 11  21.65583  03 48 50.40   +25 01 56.8   24.1R 98WS31    250  S~06AK      
2008 11  21.66208  03 48 50.35   +25 01 56.7         98WS31    250  S~06AK      
2008 11  21.66902  03 48 50.31   +25 01 56.5         98WS31    250  S~06AK      
2008 11  21.67527  03 48 50.26   +25 01 56.5         98WS31    250  S~06AK      
2008 12  22.24248  03 45 35.00   +24 51 38.6   22.1r 98WS31    695  C~0hkJ      
2008 12  22.33359  03 45 34.50   +24 51 36.6   22.0r 98WS31    695  C~0hkJ      
2016 02  04.17536  04 50 06.37   +28 27 28.5   23.3R 98WS31    G37  C~1lut      
2016 02  04.30652  04 50 06.04   +28 27 26.3         98WS31    G37  C~1lut      

The following table shows the residuals to the orbit fit. The first coumn is the point number. The second column is the time, in years, measured from the first observation. The third and fifth columns are the regularized positions used in the orbit fit. The fourth and sixth columns are the residuals, in arc seconds, for RA and Dec respectively.

  1   0.0000      0.00   473.24       0.00    45.94
  2   0.0002     -6.09   472.47       0.43    46.26
  3   0.0004    -13.37   471.41       0.52    46.24
  4   0.0814  -2197.33   154.60     -13.94    35.68
  5   0.0815  -2199.33   154.22     -13.98    35.66
  6   0.0816  -2201.26   153.96     -13.83    35.83
  7   1.0324   7243.90   258.28     905.83    32.46
  8   1.0324   7243.77   258.66     905.45    32.08
  9   1.0327   7234.59   257.32     905.58    32.20
 10   1.0328   7234.09   257.32     905.43    32.05
 11   1.1227   5300.26   -36.68     846.77    15.76
 12   1.1228   5297.06   -38.59     846.70    15.78
 13   1.1229   5298.41   -36.91     846.23    15.35
 14   1.1229   5297.91   -37.00     846.09    15.22
 15   1.1229   5297.30   -37.21     846.08    15.24
 16   1.1256   5265.69   -43.45     843.94    15.30
 17   1.1308   5212.03   -53.77     838.41    14.05
 18   1.1310   5210.41   -53.98     838.11    13.88
 19   3.8146  38716.55   761.13    3369.57   -20.15
 20   3.8149  38713.14   760.96    3369.78   -20.72
 21   9.9281  89759.15  -636.49    9546.62  -124.00
 22   9.9283  89750.61  -637.90    9547.35  -123.68
 23  10.0111  86579.76 -1068.34    9588.83  -130.08
 24  10.0111  86578.95 -1068.54    9588.86  -130.05
 25  10.0111  86578.28 -1068.54    9588.75  -130.15
 26  10.0112  86577.49 -1068.72    9588.89  -130.01
 27  10.0949  83386.23 -1489.09    9460.60  -152.59
 28  10.0951  83378.00 -1490.03    9459.85  -152.84
 29  17.2131 154378.12 -2048.33   17269.20  -208.76
 30  17.2134 154371.02 -2049.01   17266.67  -209.59

The following table comes from a 10My integration of the orbit of the object. Three columns are shown. The first column is the result of integrating the nominal orbit. The other two columns are based on clones of the nominal orbit that are +/- 3 sigma from the nominal orbit. If all three types agree then the classificiation is deemed secure. The basis for these calculations is described in more detail in AJ, 129, 1117 (2005). Any use made of these calculations should refer to and credit this publication and the Deep Ecliptic Survey Team.

98WS31    quality flag:3

Type:           3:2E      3:2E      3:2E

axisobj        39.780    39.780    39.780
ecceobj         0.209     0.209     0.209
incobj          6.727     6.727     6.727
qmin           30.917    30.917    30.917
qmax           48.290    48.289    48.290
amean          39.456    39.456    39.455
amin           39.109    39.110    39.109
amax           39.882    39.882    39.882
emean           0.195     0.195     0.195
emin            0.173     0.173     0.173
emax            0.213     0.213     0.213
imean           6.868     6.868     6.867
imin            6.238     6.239     6.238
imax            7.742     7.741     7.742
excite_mean     0.229     0.229     0.229
fracstop        1.000     1.000     1.000
cjmean          2.992     2.992     2.992

libcent 0       180.0     180.0     180.0
libamp  0        34.4      34.4      34.3
libcent 1      -180.0    -180.0    -180.0
libamp  1      -180.0    -180.0    -180.0
libcent 2      -180.0    -180.0    -180.0
libamp  2      -180.0    -180.0    -180.0
libcent 3      -180.0    -180.0    -180.0
libamp  3      -180.0    -180.0    -180.0
libcent 4      -180.0    -180.0    -180.0
libamp  4      -180.0    -180.0    -180.0

kozaimean       189.6     189.6     189.6
kozaiamp        180.0     180.0     180.0