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20947 Polyneikes (2638 T-2)
Classification: Jupiter Trojan          SPK-ID: 2020947
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

[ show orbit diagram ]
Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 30 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .02442399714819129 3.7786e-08  
a 5.069221720824104 8.487e-08 au
q 4.945411063971147 2.4829e-07 au
i 2.328143609553468 4.0787e-06 deg
node 52.24437423526182 0.00011733 deg
peri 34.46256093504812 0.00016605 deg
M 279.4553886209342 0.00011952 deg
tp 2460133.205090711217
(2023-Jul-07.70509071)
0.0013956 TDB
period 4168.793255153857
11.41
0.00010469
2.866e-07
d
yr
n .08635592555589892 2.1687e-09 deg/d
Q 5.193032377677061 8.6943e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1290  
   data-arc span      17311 days (47.39 yr)  
   first obs. used      1973-09-19  
   last obs. used      2021-02-10  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .50523  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 03:35:10  

Additional Information
 Earth MOID = 3.96161 au 
 Jupiter MOID = .0459362 au 
 T_jup = 2.998 
[ hide covariance matrix ]
Orbital Elements at Epoch 2457293.5 (2015-Sep-28.0) TDB
Reference: JPL 30 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .02275772805811157 3.7126e-08  
q 4.961733065303894 2.4494e-07 au
tp 2456005.959605480543
(2012-Mar-19.45960548)
0.0014673 TDB
node 52.28357508008257 0.00011721 deg
peri 38.15463953275534 0.0001732 deg
i 2.329331924370686 4.0784e-06 deg
  Orbit Determination Parameters
   # obs. used (total)      1290  
   data-arc span      17311 days (47.39 yr)  
   first obs. used      1973-09-19  
   last obs. used      2021-02-10  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .50523  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 03:35:10  

Additional Information
 Jupiter MOID = .0459362 au 
 T_jup = 2.998 
Orbit Covariance (6×6)
  e q tp node peri i
e 1.378373756736658E-15 -8.720075622357137E-15 -1.12341918779722E-11 1.783120624106601E-15 -1.008504822501042E-12 -2.904933372684083E-16
q -8.720075622357137E-15 5.999562647164579E-14 1.092088596234515E-10 -2.089972259306938E-14 9.850780840024588E-12 3.25865803892839E-15
tp -1.12341918779722E-11 1.092088596234515E-10 2.152976564351255E-6 -1.694467542723507E-10 1.871437270501794E-7 2.045063979839264E-11
node 1.783120624106601E-15 -2.089972259306938E-14 -1.694467542723507E-10 1.373750408702067E-8 -1.374098656848674E-8 -1.69295577799791E-10
peri -1.008504822501042E-12 9.850780840024588E-12 1.871437270501794E-7 -1.374098656848674E-8 2.999761970098413E-8 1.70984865704736E-10
i -2.904933372684083E-16 3.25865803892839E-15 2.045063979839264E-11 -1.69295577799791E-10 1.70984865704736E-10 1.663363540480961E-11

Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 11.94   n/a E2021B10  

20947 Polyneikes           Discovered 1973 Sept. 29 by C. J. van Houten and I. van Houten-Groeneveld on Palomar Schmidt plates taken by T. Gehrels.
Polyneikes was the father of Thersander, son of Oedipus and friend of Diomedes' father Tydeus. Polyneikes is a main character in The Seven against Thebes. He fought against his own brother.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: 20010309/MPCPages.arcLast Updated: 2009-05-11

Alternate Designations
 2638 T-2 = 1998 SP145 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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