Orbit Fit and Astrometric record for 98WZ31

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: 98WZ31    
# Created Wed Dec 13 02:36:58 2017
# Orbit generated from Bernstein formalism
# Fitting   26 observations of   26
# Arc:   9.92y
# First observation: 1998/11/19
#  Last observation: 2008/10/22
Preliminary a, adot, b, bdot, g, gdot:
   0.000771   0.036223  -0.000209   0.009427   0.033861   0.000000
# Chi-squared of fit:   158.21 DOF:   46 RMS:  0.44
# Min/Max residuals:    -1.37    0.76
# Exact a, adot, b, bdot, g, gdot:
  1.734728E-05  3.564929E-02  4.545317E-06  9.231968E-03  3.121463E-02  1.277121E-03
# Covariance matrix:
  2.7800E-13 -6.1229E-15 -3.1389E-15  9.9637E-15  3.9393E-13  1.0125E-13
 -6.1229E-15  1.6905E-13 -2.6952E-14  4.4803E-14  2.2481E-13  4.7523E-13
 -3.1389E-15 -2.6952E-14  8.2209E-14 -2.0565E-14 -4.1473E-14 -8.0394E-14
  9.9637E-15  4.4803E-14 -2.0565E-14  2.0914E-14  7.8061E-14  1.3556E-13
  3.9393E-13  2.2481E-13 -4.1473E-14  7.8061E-14  1.0525E-12  8.1947E-13
  1.0125E-13  4.7523E-13 -8.0394E-14  1.3556E-13  8.1947E-13  1.4361E-12
#      lat0       lon0       xBary       yBary       zBary        JD0
    1.631275   56.633880   -0.011665    0.027795   -0.983922  2451136.911951
# Heliocentric elements and errors
Epoch:              2451130.5000  =  1998/11/13
Mean Anomaly:            9.95353 +/-     0.012
Argument of Peri:      351.95799 +/-     0.017
Long of Asc Node:       50.54265 +/-     0.000
Inclination:            14.57611 +/-     0.000
Eccentricity:         0.17352563 +/-    0.0001
Semi-Major Axis:     39.77378973 +/-    0.0061
Time of Perihelion: 2448597.3047 +/-       2.9
Perihelion:          32.87201799 +/-    0.0063
Aphelion:            46.67556146 +/-    0.0081
Period (y)              250.8440 +/-      0.06
# Ecliptic coordinates at JD0 (AU and AU/d)
Ecliptic X           18.15192000 +/-    0.0006
Ecliptic Y           27.57308829 +/-    0.0009
Ecliptic Z            0.91213594 +/-    0.0000
Ecliptic XDOT        -0.00256314 +/-    0.0000
Ecliptic YDOT         0.00180308 +/-    0.0000
Ecliptic ZDOT         0.00081257 +/-    0.0000
# Distances at JD0 (AU)
Heliocenter to KBO   33.02422428 +/-    0.0008
Geocenter to KBO     32.03625889 +/-    0.0011
# Hcoef:  8.11

The following table shows the complete astrometric record for 98WZ31. 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 (98WZ31) followed by the observatory code and reference code for the source of the astrometry.

1998 11  19.41122  03 35 42.14   +20 59 22.1   22.7R 98WZ31    695  Ca3608      
1998 11  19.48013  03 35 41.68   +20 59 21.1         98WZ31    695  Ca3608      
1998 12  18.08809  03 32 47.61   +20 51 35.1         98WZ31    950  Ca3608      
1998 12  18.13019  03 32 47.34   +20 51 34.6         98WZ31    950  Ca3608      
1998 12  18.17053  03 32 47.15   +20 51 33.6         98WZ31    950  Ca3608      
1998 12  19.00361  03 32 42.74   +20 51 21.3         98WZ31    950  Ca3608      
1998 12  19.07132  03 32 42.35   +20 51 20.4         98WZ31    950  Ca3608      
1998 12  19.14566  03 32 41.90   +20 51 18.3         98WZ31    950  Ca3608      
1999 01  14.26103  03 30 54.62   +20 46 26.2   23.1R 98WZ31    695  Ca3608      
1999 01  15.16859  03 30 52.19   +20 46 20.3         98WZ31    695  Ca3608      
1999 11  30.23471  03 42 35.96   +21 55 26.6   22.8R 98WZ31    695  Ca9916      
1999 11  30.24182  03 42 35.90   +21 55 26.4   22.9R 98WZ31    695  Ca9916      
1999 11  30.38241  03 42 35.02   +21 55 24.3         98WZ31    695  Ca9916      
1999 11  30.38950  03 42 34.94   +21 55 24.2         98WZ31    695  Ca9916      
1999 12  31.25007  03 39 41.45   +21 47 47.4   22.8R 98WZ31    695  Ca9916      
1999 12  31.26647  03 39 41.39   +21 47 47.2   22.7R 98WZ31    695  Ca9916      
1999 12  31.37380  03 39 40.90   +21 47 46.4   23.3R 98WZ31    695  Ca9916      
1999 12  31.38181  03 39 40.79   +21 47 45.3   22.6R 98WZ31    695  Ca9916      
2000 01  03.24931  03 39 28.49   +21 47 11.6   23.3R 98WZ31    697  Ca9916      
2000 01  03.30771  03 39 28.23   +21 47 10.8   23.6R 98WZ31    697  Ca9916      
2000 01  05.12975  03 39 20.73   +21 46 49.6   23.5R 98WZ31    697  Ca9916      
2000 01  05.19913  03 39 20.47   +21 46 49.8   23.4R 98WZ31    697  Ca9916      
2002 01  31.05815  03 54 09.62   +23 36 24.4   23.2  98WZ31    304  Cf1458      
2002 01  31.08125  03 54 09.58   +23 36 24.1         98WZ31    304  Cf1458      
2008 10  22.33053  05 02 08.06   +29 20 19.3   23.2r 98WZ31    695  C~0gLs      
2008 10  22.41787  05 02 07.68   +29 20 19.8   23.8r 98WZ31    695  C~0gLs      

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     0.15       0.00     0.03
  2   0.0002     -6.50     0.05       0.54     0.22
  3   0.0785  -2486.49     0.37     124.63    -0.40
  4   0.0786  -2490.28    -0.16     125.05    -0.12
  5   0.0787  -2493.11     0.13     124.72    -0.59
  6   0.0810  -2556.08     0.48     127.53    -0.75
  7   0.0812  -2561.61     0.17     127.96    -0.56
  8   0.0814  -2568.24    -0.76     127.43    -1.34
  9   0.1529  -4098.94     0.32     205.23     0.09
 10   0.1554  -4133.45     0.40     207.74     0.45
 11   1.0289   6396.19     0.00    1952.78     0.44
 12   1.0290   6395.33    -0.20    1952.77     0.40
 13   1.0294   6382.91     0.28    1953.46     0.45
 14   1.0294   6381.81    -0.17    1953.61     0.57
 15   1.1139   3924.15    -0.46    2053.94     0.25
 16   1.1139   3923.29    -0.25    2053.93     0.21
 17   1.1142   3916.46    -0.14    2054.71     0.76
 18   1.1142   3914.72    -1.37    2053.99     0.02
 19   1.1221   3740.16     0.57    2060.28     0.05
 20   1.1222   3736.45     0.41    2060.33    -0.02
 21   1.1272   3629.87    -0.33    2063.56    -0.48
 22   1.1274   3626.39     0.23    2064.58     0.38
 23   3.1996  17106.00     0.16    5829.41     0.25
 24   3.1996  17105.40     0.04    5829.22     0.09
 25   9.9245  77719.67     0.07   19310.82    -0.08
 26   9.9247  77714.05     0.01   19311.67    -0.31

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.

98WZ31    quality flag:3

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

axisobj        39.877    39.895    39.858
ecceobj         0.175     0.176     0.175
incobj         14.567    14.566    14.567
qmin           32.597    32.577    32.523
qmax           46.880    46.977    46.852
amean          39.457    39.457    39.457
amin           39.027    39.021    39.049
amax           39.928    39.954    39.911
emean           0.154     0.156     0.153
emin            0.131     0.135     0.127
emax            0.175     0.176     0.175
imean          13.647    13.590    13.680
imin           12.989    13.004    12.987
imax           14.337    14.156    14.448
excite_mean     0.282     0.282     0.282
fracstop        1.000     1.000     1.000
cjmean          2.961     2.961     2.961

libcent 0       180.3     180.1     178.7
libamp  0        90.0      96.4      80.8
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       184.8     184.9     179.9
kozaiamp        180.0     180.0     179.9