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(2009 HD21)
Classification: Apollo [NEO, PHA]          SPK-ID: 3457843
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]

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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.


Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 46 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .6881621438938398 2.6329e-08  
a 2.771934999524019 7.2144e-08 au
q .8643942675172002 8.1387e-08 au
i 18.64196326248386 2.4118e-05 deg
node 179.23590095273 2.2113e-05 deg
peri 134.2529964047759 2.3309e-05 deg
M 164.3062531490924 3.5222e-05 deg
tp 2458431.148896055385
(2018-Nov-08.64889606)
0.00013491 TDB
period 1685.6716778073
4.62
6.5808e-05
1.802e-07
d
yr
n .2135647200694998 8.3375e-09 deg/d
Q 4.679475731530837 1.2179e-07 au
  Orbit Determination Parameters
   # obs. used (total)      146  
   data-arc span      3281 days (8.98 yr)  
   first obs. used      2009-03-24  
   last obs. used      2018-03-18  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .48319  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-15 02:42:37  

Additional Information
 Earth MOID = .0126196 au 
 Jupiter MOID = 1.30922 au 
 T_jup = 2.881 
[ show covariance matrix ]

Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 18.2   n/a MPO166339  

[ show close-approach data ]
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]
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