Orbit Fit and Astrometric record for 98WY31

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: 98WY31    
# Created Sun Oct 21 01:07:26 2018
# Orbit generated by ELGB
# -->Covariance matrix from a Bernstein fit
# Fitting   23 observations of   23
# Arc:  16.25y
# First observation: 1998/11/18
#  Last observation: 2015/02/18
# Chi-squared of fit:    16.45 DOF:   40 RMS:  0.15
# Min/Max residuals:    -0.26    0.35
# Exact a, adot, b, bdot, g, gdot:
  1.546979E-05  2.088756E-02  1.105837E-06  7.097764E-04  2.254171E-02 -2.342871E-03
# Covariance matrix:
  4.3858E-13 -1.0413E-13  5.6651E-15 -3.1780E-15  2.2836E-13 -2.9406E-13
 -1.0413E-13  3.9677E-14 -2.3388E-15  1.3242E-15 -4.0167E-14  1.2056E-13
  5.6651E-15 -2.3388E-15  1.3705E-13 -1.3206E-14  2.4702E-15 -7.5377E-15
 -3.1780E-15  1.3242E-15 -1.3206E-14  2.3170E-15 -1.3505E-15  4.2676E-15
  2.2836E-13 -4.0167E-14  2.4702E-15 -1.3505E-15  2.5580E-13 -1.3066E-13
 -2.9406E-13  1.2056E-13 -7.5377E-15  4.2676E-15 -1.3066E-13  3.8856E-13
#      lat0       lon0       xBary       yBary       zBary        JD0
    0.340721   73.748801    0.294934    0.005359   -0.939233  2451135.927691
# Heliocentric elements and errors
Epoch:              2451136.5000  =  1998/11/19
Mean Anomaly:          276.85946 +/-     0.026
Argument of Peri:      106.02766 +/-     0.037
Long of Asc Node:       63.63416 +/-     0.001
Inclination:             1.97336 +/-     0.000
Eccentricity:         0.11459247 +/-    0.0000
Semi-Major Axis:     45.33059590 +/-    0.0043
Time of Perihelion: 2476881.6774 +/-      14.7
Perihelion:          40.13605081 +/-    0.0040
Aphelion:            50.52514100 +/-    0.0050
Period (y)              305.2076 +/-      0.04
# Ecliptic coordinates at JD0 (AU and AU/d)
Ecliptic X           12.96822405 +/-    0.0003
Ecliptic Y           43.40758900 +/-    0.0010
Ecliptic Z            0.26386220 +/-    0.0000
Ecliptic XDOT        -0.00251595 +/-    0.0000
Ecliptic YDOT         0.00044539 +/-    0.0000
Ecliptic ZDOT         0.00008449 +/-    0.0000
# Distances at JD0 (AU)
Heliocenter to KBO   45.30419431 +/-    0.0009
Geocenter to KBO     44.36230298 +/-    0.0010
# Hcoef:  6.85

The following table shows the complete astrometric record for 98WY31. 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 (98WY31) followed by the observatory code and reference code for the source of the astrometry.

1998 11  18.42696  04 49 19.14   +22 47 19.1   23.1R 98WY31    695  Ca3608      
1998 11  18.49839  04 49 18.81   +22 47 18.7         98WY31    695  Ca3608      
1999 01  15.19486  04 44 53.45   +22 39 55.9   23.7R 98WY31    695  Ca3608      
1999 01  15.29128  04 44 53.08   +22 39 55.3         98WY31    695  Ca3608      
2000 12  22.41733  04 56 51.41   +23 04 29.2   23.3R 98WY31    568  Cc3588      
2000 12  23.36594  04 56 46.85   +23 04 22.4         98WY31    568  Cc3588      
2000 12  23.43951  04 56 46.50   +23 04 21.9         98WY31    568  Cc3588      
2000 12  27.28716  04 56 28.329  +23 03 55.28        98WY31    568  Cl2504      
2000 12  27.35794  04 56 27.987  +23 03 54.98        98WY31    568  Cl2504      
2001 01  25.12123  04 54 36.30   +23 01 05.1   24.0R 98WY31    695  Cc6418      
2001 01  25.15704  04 54 36.19   +23 01 05.3         98WY31    695  Cc6418      
2001 01  25.19465  04 54 36.07   +23 01 04.8         98WY31    695  Cc6418      
2002 01  30.07841  04 59 34.49   +23 10 58.8   21.1  98WY31    304  Cf1458      
2002 01  30.10037  04 59 34.44   +23 10 58.7         98WY31    304  Cf1458      
2008 11  02.95374  05 43 32.22   +24 07 41.6   26.5R 98WY31    250  S~06AK      
2008 11  02.95999  05 43 32.19   +24 07 41.5         98WY31    250  S~06AK      
2008 11  02.96694  05 43 32.17   +24 07 41.5         98WY31    250  S~06AK      
2008 11  02.97388  05 43 32.13   +24 07 41.4         98WY31    250  S~06AK      
2008 12  21.39721  05 39 48.36   +24 06 40.4   22.6r 98WY31    695  C~0hkJ      
2008 12  21.47242  05 39 47.97   +24 06 40.0   22.7r 98WY31    695  C~0hkJ      
2008 12  22.37989  05 39 43.29   +24 06 38.3   22.8r 98WY31    695  C~0hkJ      
2015 02  18.15116  06 09 16.07   +24 24 36.4   22.0R 98WY31    695  C~1M5z      
2015 02  18.19828  06 09 15.92   +24 24 36.5         98WY31    695  C~1M5z      

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    -0.17       0.00    -0.14
  2   0.0002      0.00    -0.01       0.00     0.00
  3   0.1582      0.00     0.29       0.00     0.01
  4   0.1584      0.00    -0.11       0.00     0.02
  5   2.0944      0.00     0.03       0.00     0.04
  6   2.0970      0.00    -0.10       0.00    -0.13
  7   2.0972      0.00     0.03       0.00    -0.12
  8   2.1078      0.00    -0.12       0.00    -0.13
  9   2.1080      0.00    -0.22       0.00     0.04
 10   2.1867      0.00     0.17       0.00    -0.10
 11   2.1868      0.00     0.13       0.00     0.27
 12   2.1869      0.00     0.01       0.00    -0.06
 13   3.1996      0.00    -0.09       0.00     0.01
 14   3.1997      0.00     0.05       0.00    -0.00
 15   9.9590      0.00     0.11       0.00     0.35
 16   9.9590      0.00    -0.02       0.00     0.25
 17   9.9590      0.00     0.03       0.00     0.25
 18   9.9591      0.00    -0.22       0.00     0.15
 19  10.0916      0.00    -0.17       0.00     0.04
 20  10.0918      0.00    -0.13       0.00    -0.17
 21  10.0943      0.00    -0.05       0.00     0.08
 22  16.2511      0.00     0.21       0.00    -0.26
 23  16.2513      0.00    -0.23       0.00    -0.14

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.

98WY31    quality flag:3

Type:      CLASSICAL CLASSICAL CLASSICAL

axisobj        45.489    45.489    45.489
ecceobj         0.116     0.116     0.116
incobj          1.973     1.973     1.973
qmin           39.121    39.042    39.140
qmax           51.695    51.733    51.679
amean          45.255    45.254    45.255
amin           44.879    44.879    44.879
amax           45.660    45.667    45.667
emean           0.118     0.118     0.118
emin            0.103     0.103     0.103
emax            0.132     0.133     0.132
imean           1.113     1.113     1.113
imin            0.326     0.326     0.326
imax            1.680     1.682     1.681
excite_mean     0.120     0.119     0.120
fracstop        1.000     1.000     1.000
cjmean          3.099     3.099     3.099

libcent 0      -180.0    -180.0    -180.0
libamp  0      -180.0    -180.0    -180.0
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       168.8     168.8     168.8
kozaiamp        179.9     180.0     179.9