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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.


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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 45 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .6881359812853384 2.6986e-08  
a 2.771807630029484 7.3827e-08 au
q .8644270666049567 8.382e-08 au
i 18.63813621971146 2.4371e-05 deg
node 179.2537132684909 2.2187e-05 deg
peri 134.2274346855696 2.3621e-05 deg
M 121.6267314518585 3.4418e-05 deg
tp 2458431.031651264398
(2018-Nov-08.53165126)
0.00013841 TDB
period 1685.555495059587
4.61
6.7342e-05
1.844e-07
d
yr
n .2135794407571691 8.5331e-09 deg/d
Q 4.67918819345401 1.2463e-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.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .46975  
   source      ORB  
   producer      Otto Matic  
   solution date      2018-Mar-19 06:25:31  

Additional Information
 Earth MOID = .0114532 au 
 Jupiter MOID = 1.30938 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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