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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 ]

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For accurate long-term ephemerides, please instead use our Horizons system.This orbit viewer was implemented using two-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances.


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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 26 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .02410526386649262 4.108e-08  
a 5.069603953220068 9.1261e-08 au
q 4.947399812229085 2.5327e-07 au
i 2.328108507790466 4.5855e-06 deg
node 52.24586466479368 0.00012316 deg
peri 34.27471152816796 0.00017288 deg
M 262.3348594593076 0.00012372 deg
tp 2460131.588416058275
(2023-Jul-06.08841606)
0.0014487 TDB
period 4169.264770691871
11.41
0.00011258
3.082e-07
d
yr
n .0863461592870389 2.3315e-09 deg/d
Q 5.191808094211052 9.346e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1094  
   data-arc span      17117 days (46.86 yr)  
   first obs. used      1973-09-19  
   last obs. used      2020-07-31  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .52543  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Aug-25 01:40:21  

Additional Information
 Earth MOID = 3.96393 au 
 Jupiter MOID = .045874 au 
 T_jup = 2.998 
[ hide covariance matrix ]
Orbital Elements at Epoch 2456706.5 (2014-Feb-18.0) TDB
Reference: JPL 26 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .02387944997597127 4.0129e-08  
q 4.962936539440011 2.4795e-07 au
tp 2456040.078181961861
(2012-Apr-22.57818196)
0.0014355 TDB
node 52.31188459936462 0.00012304 deg
peri 41.11803937217842 0.00017503 deg
i 2.328618222544121 4.5822e-06 deg
  Orbit Determination Parameters
   # obs. used (total)      1094  
   data-arc span      17117 days (46.86 yr)  
   first obs. used      1973-09-19  
   last obs. used      2020-07-31  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .52543  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Aug-25 01:40:21  

Additional Information
 Jupiter MOID = .045874 au 
 T_jup = 2.998 
Orbit Covariance (6×6)
  e q tp node peri i
e 1.610348003585251E-15 -9.314083160398329E-15 -5.597030660747375E-12 4.793986426435262E-18 -5.317972981575855E-13 -1.058373853338359E-16
q -9.314083160398329E-15 6.147891216897869E-14 9.131259406337535E-11 -1.666109526182907E-14 8.311956642753376E-12 2.16694517094875E-15
tp -5.597030660747375E-12 9.131259406337535E-11 2.060772649643233E-6 -2.962141060483814E-10 1.787557672648744E-7 1.187419073072949E-11
node 4.793986426435262E-18 -1.666109526182907E-14 -2.962141060483814E-10 1.513946710932579E-8 -1.515265584627453E-8 -9.233710592492485E-11
peri -5.317972981575855E-13 8.311956642753376E-12 1.787557672648744E-7 -1.515265584627453E-8 3.06359436304401E-8 9.333477764441657E-11
i -1.058373853338359E-16 2.16694517094875E-15 1.187419073072949E-11 -9.233710592492485E-11 9.333477764441657E-11 2.099650828962373E-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 11.9   n/a MPO412340  

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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