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1872 Helenos (1971 FG)
Classification: Jupiter Trojan          SPK-ID: 2001872
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 24 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .04903770725066579 4.29e-08  
a 5.32115368736261 8.7686e-08 au
q 5.060216510605922 2.8832e-07 au
i 14.64015029890449 4.7562e-06 deg
node 188.7871755774364 1.5204e-05 deg
peri 114.6330066032064 5.4706e-05 deg
M 309.0948207661513 5.3739e-05 deg
tp 2459834.466925215232
(2022-Sep-11.96692521)
0.00067335 TDB
period 4483.396316690038
12.27
0.00011082
3.034e-07
d
yr
n .08029626974083291 1.9848e-09 deg/d
Q 5.582090864119299 9.1986e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1858  
   data-arc span      24000 days (65.71 yr)  
   first obs. used      1954-12-22  
   last obs. used      2020-09-06  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .46503  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Nov-13 04:14:43  

Additional Information
 Earth MOID = 4.07545 au 
 Jupiter MOID = .0664304 au 
 T_jup = 2.932 
[ hide covariance matrix ]
Orbital Elements at Epoch 2457423.5 (2016-Feb-05.0) TDB
Reference: JPL 24 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .04761871256370111 4.2643e-08  
q 5.064980873923145 2.8699e-07 au
tp 2455377.899928045631
(2010-Jun-30.39992805)
0.00067459 TDB
node 188.7920592782487 1.5206e-05 deg
peri 116.2868620401956 5.6491e-05 deg
i 14.64126647560273 4.7564e-06 deg
  Orbit Determination Parameters
   # obs. used (total)      1858  
   data-arc span      24000 days (65.71 yr)  
   first obs. used      1954-12-22  
   last obs. used      2020-09-06  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .46503  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Nov-13 04:14:43  

Additional Information
 Jupiter MOID = .0664304 au 
 T_jup = 2.932 
Orbit Covariance (6×6)
  e q tp node peri i
e 1.818432085397351E-15 -1.190550326632038E-14 -3.888819056812376E-12 1.742000306164838E-15 -3.536367847801615E-13 4.876765391975872E-16
q -1.190550326632038E-14 8.236163818258767E-14 2.753650141514456E-11 -8.697388836088842E-15 2.706026003727408E-12 -4.184500239350951E-15
tp -3.888819056812376E-12 2.753650141514456E-11 4.55071540956751E-7 -8.939662950652855E-11 3.666525492722417E-8 1.945115094773008E-11
node 1.742000306164838E-15 -8.697388836088842E-15 -8.939662950652855E-11 2.312103207586395E-10 -2.306664525280804E-10 2.089617387743183E-11
peri -3.536367847801615E-13 2.706026003727408E-12 3.666525492722417E-8 -2.306664525280804E-10 3.19124679990146E-9 -1.878611180736833E-11
i 4.876765391975872E-16 -4.184500239350951E-15 1.945115094773008E-11 2.089617387743183E-11 -1.878611180736833E-11 2.26234945924009E-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 10.88   n/a E2021B10  
diameter diameter 34.046 km 0.603 urn:nasa:pds:neowise_diameters_albedos::2.0[jupiter_trojans] (http://adsabs.harvard.edu/abs/2012ApJ...759...49G)  
geometric albedo albedo 0.067   0.012 urn:nasa:pds:neowise_diameters_albedos::2.0[jupiter_trojans] (http://adsabs.harvard.edu/abs/2012ApJ...759...49G)  

1872 Helenos (1971 FG)          Discovered 1971-Mar-24 by Van Houten, C. J. at Palomar
Discovered by C. J. van Houten and I. van Houten-Groeneveld, Leiden, on plates exposed by T. Gehrels in a survey of faint Trojans with the 122 cm Schmidt camera at Palomar.
Reference: DISCOVERY.DBLast Updated: 2003-08-29
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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