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2684 Douglas (1981 AH1)
Classification: Main-belt Asteroid          SPK-ID: 2002684
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | 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 2459000.5 (2020-May-31.0) TDB
Reference: JPL 39 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .04715343564257046 3.3655e-08  
a 3.052064070221236 1.5248e-08 au
q 2.908148763509057 1.0619e-07 au
i 9.922757718221025 4.1527e-06 deg
node 150.7127451069952 2.3311e-05 deg
peri 112.1663507940754 5.3126e-05 deg
M 10.65813344901046 4.7154e-05 deg
tp 2458942.840941159580
(2020-Apr-03.34094116)
0.00025516 TDB
period 1947.551255748102
5.33
1.4595e-05
3.996e-08
d
yr
n .1848475098858003 1.3852e-09 deg/d
Q 3.195979376933415 1.5967e-08 au
  Orbit Determination Parameters
   # obs. used (total)      2422  
   data-arc span      22172 days (60.70 yr)  
   first obs. used      1960-02-27  
   last obs. used      2020-11-10  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .42776  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Dec-18 02:07:45  

Additional Information
 Earth MOID = 1.91046 au 
 Jupiter MOID = 1.89266 au 
 T_jup = 3.212 
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Orbital Elements at Epoch 2456685.5 (2014-Jan-28.0) TDB
Reference: JPL 39 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .04451031103456809 3.3738e-08  
q 2.912789167694062 1.0596e-07 au
tp 2457001.593318570718
(2014-Dec-10.09331857)
0.00027183 TDB
node 150.7884503977256 2.3332e-05 deg
peri 112.8215813453355 5.5651e-05 deg
i 9.920386755908867 4.1525e-06 deg
  Orbit Determination Parameters
   # obs. used (total)      2422  
   data-arc span      22172 days (60.70 yr)  
   first obs. used      1960-02-27  
   last obs. used      2020-11-10  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .42776  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Dec-18 02:07:45  

Additional Information
 Jupiter MOID = 1.89266 au 
 T_jup = 3.212 
Orbit Covariance (6×6)
  e q tp node peri i
e 1.138237298038007E-15 -3.540950047960658E-15 -5.312357322811406E-13 1.483627495845714E-15 -9.241840056017447E-14 4.153661784285162E-17
q -3.540950047960658E-15 1.122691442553928E-14 9.244531328607171E-13 -4.400656949810347E-15 1.449627398277628E-13 1.356053883744695E-15
tp -5.312357322811406E-13 9.244531328607171E-13 7.389267092787867E-8 -2.472808688220213E-11 1.375638148644706E-8 -3.705812018634324E-12
node 1.483627495845714E-15 -4.400656949810347E-15 -2.472808688220213E-11 5.44363517266856E-10 -5.4039659359595E-10 1.665498555660359E-11
peri -9.241840056017447E-14 1.449627398277628E-13 1.375638148644706E-8 -5.4039659359595E-10 3.097049880306826E-9 -1.702412463367975E-11
i 4.153661784285162E-17 1.356053883744695E-15 -3.705812018634324E-12 1.665498555660359E-11 -1.702412463367975E-11 1.724303581186152E-11

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

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 11.6   n/a MPO337270  
diameter diameter 15.962 km 0.255 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
geometric albedo albedo 0.159   0.008 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

2684 Douglas (1981 AH1)          Discovered 1981-Jan-03 by Thomas, N. G. at Flagstaff (AM)
Discovered at the Anderson Mesa station, which is operated by the Lowell Observatory.
Reference: DISCOVERY.DBLast Updated: 2003-08-29

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Alternate Designations
 1981 AH1 = 1960 DE = 1972 NY = 1978 PO2 = 1978 RU4 = 1978 SE4 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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