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18306 (1981 EF9)
Classification: Main-belt Asteroid          SPK-ID: 2018306
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 25 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1048736434948502 4.8304e-08  
a 2.308955776762398 8.7779e-09 au
q 2.066807171784844 1.1069e-07 au
i 3.983438681056565 4.0226e-06 deg
node 283.7384372580095 6.8679e-05 deg
peri 262.4096451453885 7.1026e-05 deg
M 114.1174530953833 1.828e-05 deg
tp 2458794.270536748762
(2019-Nov-06.77053675)
6.4877e-05 TDB
period 1281.509557071967
3.51
7.3078e-06
2.001e-08
d
yr
n .2809187009284108 1.6019e-09 deg/d
Q 2.551104381739953 9.6984e-09 au
  Orbit Determination Parameters
   # obs. used (total)      1364  
   data-arc span      14915 days (40.84 yr)  
   first obs. used      1979-10-18  
   last obs. used      2020-08-18  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .51875  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 02:26:18  

Additional Information
 Earth MOID = 1.07213 au 
 Jupiter MOID = 2.42555 au 
 T_jup = 3.575 
[ show covariance matrix ]

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 14.88   n/a E2021B10  
diameter diameter 2.617 km 0.271 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
geometric albedo albedo 0.409   0.055 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

18306 (1981 EF9)          Discovered 1981-Mar-01 by Bus, S. J. at Siding Spring
Reference: 20001111/Numbers.arcLast Updated: 2004-04-19

[ show close-approach data ]
Alternate Designations
 1981 EF9 = 2000 SX168 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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