Orbit Fit and Astrometric record for 21DK18

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: 21DK18    
# Created Tue Apr  1 01:11:24 2025
# Orbit generated from Bernstein formalism
# Fitting     18 observations of     18
# Arc:   4.03y
# First observation: 2020/02/26
#  Last observation: 2024/03/08
Preliminary a, adot, b, bdot, g, gdot:
  -0.000335   0.012826   0.000099  -0.003365   0.015040   0.000000
# Chi-squared of fit:     5.17 DOF:     30 RMS:  0.09
# Min/Max residuals:    -0.22    0.19
# Exact a, adot, b, bdot, g, gdot:
  1.339527E-05  1.237406E-02 -2.725045E-06 -3.240447E-03  1.493296E-02 -9.227189E-03
# Covariance matrix:
  5.5123E-13 -5.0468E-13 -7.8493E-14  1.0560E-13 -1.6623E-13 -7.4554E-12
 -5.0468E-13  6.2310E-13  1.1195E-13 -1.5116E-13  1.8921E-13  1.0664E-11
 -7.8493E-14  1.1195E-13  2.9845E-13 -1.4811E-13  3.8967E-14  2.1593E-12
  1.0560E-13 -1.5116E-13 -1.4811E-13  1.1166E-13 -4.9573E-14 -2.9168E-12
 -1.6623E-13  1.8921E-13  3.8967E-14 -4.9573E-14  3.3079E-13  3.5426E-12
 -7.4554E-12  1.0664E-11  2.1593E-12 -2.9168E-12  3.5426E-12  2.0575E-10
#      lat0       lon0       xBary       yBary       zBary        JD0
    4.871702  124.039590   -0.533701    0.071503   -0.838830  2458905.627206
# Heliocentric elements and errors
Epoch:              2458900.5000  =  2020/02/21
Mean Anomaly:          358.96263 +/-     0.034
Argument of Peri:      235.25905 +/-     0.029
Long of Asc Node:      322.19596 +/-     0.001
Inclination:            15.47338 +/-     0.001
Eccentricity:         0.94083443 +/-    0.0013
Semi-Major Axis:    747.41266735 +/-   16.4549
Time of Perihelion: 2480407.0222 +/-      10.4
Perihelion:          44.22109504 +/-    1.3993
Aphelion:          1450.60423966 +/-   31.9521
Period (y)            20433.7880 +/-    674.80
# Ecliptic coordinates at JD0 (AU and AU/d)
Ecliptic X          -38.25980707 +/-    0.0015
Ecliptic Y           55.68200082 +/-    0.0021
Ecliptic Z            5.68684614 +/-    0.0002
Ecliptic XDOT        -0.00095641 +/-    0.0000
Ecliptic YDOT        -0.00262241 +/-    0.0000
Ecliptic ZDOT        -0.00073587 +/-    0.0000
# Distances at JD0 (AU)
Heliocenter to KBO   67.79851231 +/-    0.0019
Geocenter to KBO     66.96595215 +/-    0.0026
# Hcoef:  6.69

The following table shows the complete astrometric record for 21DK18. 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 (21DK18) followed by the observatory code and reference code for the source of the astrometry.

2020 02  26.126405 08 30 28.59   +23 58 31.5   24.5V 21DK18    W84  C~5rBm      
2020 02  26.128468 08 30 28.60   +23 58 31.8         21DK18    W84  C~5rBm      
2021 02  17.25324  08 33 41.803  +23 36 13.90  24.6r 21DK18    568  C~5oWe      
2021 02  17.42570  08 33 41.264  +23 36 15.15  24.6r 21DK18    568  C~5oWe      
2021 03  09.06636  08 32 47.221  +23 37 58.38  24.8G 21DK18    304  C~5oWe      
2021 03  09.11920  08 32 47.096  +23 37 58.77  24.6G 21DK18    304  C~5oWe      
2021 03  17.12379  08 32 29.682  +23 38 17.80  24.8r 21DK18    304  C~5oWe      
2021 03  18.08040  08 32 27.824  +23 38 19.02  24.7r 21DK18    304  C~5oWe      
2021 12  02.30868  08 40 17.453  +23 01 37.40  24.8r 21DK18    304  C~5oWe      
2021 12  06.29584  08 40 10.633  +23 02 08.57  24.9r 21DK18    304  C~5oWe      
2021 12  07.30601  08 40 08.763  +23 02 17.17  24.7r 21DK18    304  C~5oWe      
2022 03  07.03706  08 35 43.775  +23 15 52.22  25.2G 21DK18    304  C~5oWe      
2022 03  07.04747  08 35 43.731  +23 15 52.23  25.1G 21DK18    304  C~5oWe      
2022 03  07.12631  08 35 43.531  +23 15 52.81  25.2G 21DK18    304  C~5oWe      
2022 03  07.13663  08 35 43.516  +23 15 52.87  25.1G 21DK18    304  C~5oWe      
2022 04  09.02361  08 34 48.790  +23 16 05.74  24.8r 21DK18    304  C~5oWe      
2024 03  07.05906  08 41 31.929  +22 30 05.22  24.9r 21DK18    304  C~7um0      
2024 03  08.05293  08 41 29.398  +22 30 09.83  25.0r 21DK18    304  C~7um0      

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    -0.06       0.00    -0.15
     2   0.0000      0.06     0.08       0.32     0.19
     3   0.9778   2899.98     0.02    -642.84    -0.02
     4   0.9782   2892.49     0.03    -643.47    -0.00
     5   1.0320   2147.28    -0.07    -727.97    -0.12
     6   1.0322   2145.52    -0.08    -728.01     0.10
     7   1.0541   1908.92    -0.02    -768.77     0.05
     8   1.0567   1883.88     0.11    -773.90    -0.03
     9   1.7664   8704.27     0.12   -1263.23     0.14
    10   1.7773   8605.08     0.00   -1257.60    -0.10
    11   1.7801   8577.87    -0.13   -1256.00     0.13
    12   2.0258   4832.22     0.14   -1404.54    -0.12
    13   2.0258   4831.63    -0.08   -1404.68    -0.22
    14   2.0260   4828.81    -0.12   -1404.81     0.03
    15   2.0260   4828.60     0.03   -1404.81     0.09
    16   2.1161   4095.17     0.02   -1582.24    -0.05
    17   4.0272  10196.37     0.01   -2822.84     0.10
    18   4.0299  10161.23     0.00   -2827.58    -0.04

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.

21DK18    quality flag:1

Type:       SCATNEAR  SCATNEAR  SCATNEAR

axisobj       759.339   810.804   714.199
ecceobj         0.941     0.945     0.937
incobj         15.440    15.440    15.441
qmin           36.957    36.569    37.384
qmax         1829.075  2045.828  1777.582
amean         762.778   818.541   734.521
amin          692.104   711.976   671.118
amax          936.748  1045.075   911.039
emean           0.942     0.946     0.939
emin            0.929     0.933     0.928
emax            0.953     0.958     0.951
imean          16.731    16.742    16.729
imin           16.005    15.977    16.052
imax           17.587    17.693    17.529
excite_mean     0.985     0.989     0.982
fracstop        1.000     1.000     1.000
cjmean          3.283     3.280     3.286

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       237.2     236.9     237.1
kozaiamp          6.6       6.7       6.6