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

[ show orbit diagram ]
Orbital Elements at Epoch 2457600.5 (2016-Jul-31.0) TDB
Reference: JPL 19 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .02260871007698451 6.1954e-08  
a 5.075411698400033 1.1787e-07 au
q 4.960663186789571 3.1582e-07 au
i 2.329378888508901 6.8523e-06 deg
node 52.28271251575039 0.00016302 deg
peri 36.75614708618572 0.00025606 deg
M 138.8291123441424 0.00019352 deg
tp 2455989.915973634701
(2012-Mar-03.41597363)
0.0022454 JED
period 4176.43129529072
11.43
0.00014549
3.983e-07
d
yr
n .08619799406395851 3.0027e-09 deg/d
Q 5.190160210010495 1.2053e-07 au
  Orbit Determination Parameters
   # obs. used (total)      896  
   data-arc span      15551 days (42.58 yr)  
   first obs. used      1973-09-19  
   last obs. used      2016-04-17  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-BIG16  
   condition code      0  
   fit RMS      .52001  
   data source      ORB  
   producer      Otto Matic  
   solution date      2016-Apr-25 13:35:48  

Additional Information
 Earth MOID = 3.97577 au 
 Jupiter MOID = .0557374 au 
 T_jup = 2.998 
[ show covariance matrix ]

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

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 12.0 mag n/a MPO337435  

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 | Physical Parameters | Discovery Circumstances ]
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